Raid0 with btrfs

Raid0 with btrfs

[Leonidas Spyropoulos]

Hi all,

I want to make a btrfs raid0 on 2 partitions of my pc.
Until now I am using the mdadm tools to make a software raid of the 2
partitions /dev/sde2, /dev/sdd2
and then mkfs.etx4 the newly created /dev/md0 device.
>From performance point of view is it better to keep the configuration of mdadm
and just format the /dev/md0 device as btrfs OR
delete the raid device and format the 2 partitions /dev/sde2 /dev/sdd2
as a btrfs with 2 devices?
mkfs.btrfs /dev/sde2 /dev/sdd2

On a sidenote:
If I decide to go for raid5 which is not supported currently from mkfs
I have to use the mdadm tool anyway, right?

-- 
Caution: breathing may be hazardous to your health.

Re: Raid0 with btrfs

[Hubert Kario]

On Thursday 05 August 2010 16:15:22 Leonidas Spyropoulos wrote:
> Hi all,
>=20
> I want to make a btrfs raid0 on 2 partitions of my pc.
> Until now I am using the mdadm tools to make a software raid of the 2
> partitions /dev/sde2, /dev/sdd2
> and then mkfs.etx4 the newly created /dev/md0 device.
> From performance point of view is it better to keep the configuration=
 of
> mdadm and just format the /dev/md0 device as btrfs OR
> delete the raid device and format the 2 partitions /dev/sde2 /dev/sdd=
2
> as a btrfs with 2 devices?
> mkfs.btrfs /dev/sde2 /dev/sdd2

Btrfs already supports metadata mirroring when the data is striped. Wha=
t this=20
means, is while the performance should be more-or-less identical to MD =
RAID0=20
(if it isn't it's a bug), your data is a bit more secure as the metadat=
a=20
describing it resides on both drives. Later on it will be possible to s=
elct=20
which directories/files should have what level of redundancy. This will=
 allow=20
to have ~/work RAID1-ed and ~/videos RAID0-ed while keeping both direct=
ories=20
on the same partition and filesystem.

> On a sidenote:
> If I decide to go for raid5 which is not supported currently from mkf=
s
> I have to use the mdadm tool anyway, right?

yes, RAID5 code is not in trunk yet.

--=20
Hubert Kario
QBS - Quality Business Software
02-656 Warszawa, ul. Ksawer=F3w 30/85
tel. +48 (22) 646-61-51, 646-74-24
www.qbs.com.pl
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" =
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Re: Raid0 with btrfs

[Leonidas Spyropoulos]

Do I have to change the partition ID flag of each partition?
Currently is set to fd (Linux Raid autodetect) for used from mdadm
mkfs.btrfs supports that or needs to be 83 (Linux) ?


On Thu, Aug 5, 2010 at 3:40 PM, Hubert Kario <hka@qbs.com.pl> wrote:
> On Thursday 05 August 2010 16:15:22 Leonidas Spyropoulos wrote:
>> Hi all,
>>
>> I want to make a btrfs raid0 on 2 partitions of my pc.
>> Until now I am using the mdadm tools to make a software raid of the =
2
>> partitions /dev/sde2, /dev/sdd2
>> and then mkfs.etx4 the newly created /dev/md0 device.
>> From performance point of view is it better to keep the configuratio=
n of
>> mdadm and just format the /dev/md0 device as btrfs OR
>> delete the raid device and format the 2 partitions /dev/sde2 /dev/sd=
d2
>> as a btrfs with 2 devices?
>> mkfs.btrfs /dev/sde2 /dev/sdd2
>
> Btrfs already supports metadata mirroring when the data is striped. W=
hat this
> means, is while the performance should be more-or-less identical to M=
D RAID0
> (if it isn't it's a bug), your data is a bit more secure as the metad=
ata
> describing it resides on both drives. Later on it will be possible to=
 selct
> which directories/files should have what level of redundancy. This wi=
ll allow
> to have ~/work RAID1-ed and ~/videos RAID0-ed while keeping both dire=
ctories
> on the same partition and filesystem.
>
>> On a sidenote:
>> If I decide to go for raid5 which is not supported currently from mk=
fs
>> I have to use the mdadm tool anyway, right?
>
> yes, RAID5 code is not in trunk yet.
>
> --
> Hubert Kario
> QBS - Quality Business Software
> 02-656 Warszawa, ul. Ksawer=F3w 30/85
> tel. +48 (22) 646-61-51, 646-74-24
> www.qbs.com.pl
>



--=20
Caution: breathing may be hazardous to your health.
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Re: Raid0 with btrfs

[Sebastian 'gonX' Jensen]

On 6 August 2010 20:23, Leonidas Spyropoulos <artafinde@gmail.com> wrot=
e:
> Do I have to change the partition ID flag of each partition?
> Currently is set to fd (Linux Raid autodetect) for used from mdadm
> mkfs.btrfs supports that or needs to be 83 (Linux) ?

=46D is for mdraid integrated into the Linux kernel. I have mine at 83.
It won't hurt to have them at FD, but the kernel will spend extra time
as it probes the devices on boot, causing a slight slowdown.
>
> On Thu, Aug 5, 2010 at 3:40 PM, Hubert Kario <hka@qbs.com.pl> wrote:
>> On Thursday 05 August 2010 16:15:22 Leonidas Spyropoulos wrote:
>>> Hi all,
>>>
>>> I want to make a btrfs raid0 on 2 partitions of my pc.
>>> Until now I am using the mdadm tools to make a software raid of the=
 2
>>> partitions /dev/sde2, /dev/sdd2
>>> and then mkfs.etx4 the newly created /dev/md0 device.
>>> From performance point of view is it better to keep the configurati=
on of
>>> mdadm and just format the /dev/md0 device as btrfs OR
>>> delete the raid device and format the 2 partitions /dev/sde2 /dev/s=
dd2
>>> as a btrfs with 2 devices?
>>> mkfs.btrfs /dev/sde2 /dev/sdd2
>>
>> Btrfs already supports metadata mirroring when the data is striped. =
What this
>> means, is while the performance should be more-or-less identical to =
MD RAID0
>> (if it isn't it's a bug), your data is a bit more secure as the meta=
data
>> describing it resides on both drives. Later on it will be possible t=
o selct
>> which directories/files should have what level of redundancy. This w=
ill allow
>> to have ~/work RAID1-ed and ~/videos RAID0-ed while keeping both dir=
ectories
>> on the same partition and filesystem.
>>
>>> On a sidenote:
>>> If I decide to go for raid5 which is not supported currently from m=
kfs
>>> I have to use the mdadm tool anyway, right?
>>
>> yes, RAID5 code is not in trunk yet.
>>
>> --
>> Hubert Kario
>> QBS - Quality Business Software
>> 02-656 Warszawa, ul. Ksawer=C3=B3w 30/85
>> tel. +48 (22) 646-61-51, 646-74-24
>> www.qbs.com.pl
>>
>
>
>
> --
> Caution: breathing may be hazardous to your health.
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs=
" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at =C2=A0http://vger.kernel.org/majordomo-info.ht=
ml
>

Regards,
Sebastian J.

PS. Please try to bottom-post rather than top-post. Here's a link I
can advise reading for a clarification on why bottom posting is
essential: http://www.caliburn.nl/topposting.html
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Re: Raid0 with btrfs

[Leonidas Spyropoulos]

On Fri, Aug 6, 2010 at 7:32 PM, Sebastian 'gonX' Jensen
<gonx@overclocked.net> wrote:
> On 6 August 2010 20:23, Leonidas Spyropoulos <artafinde@gmail.com> wr=
ote:
>> Do I have to change the partition ID flag of each partition?
>> Currently is set to fd (Linux Raid autodetect) for used from mdadm
>> mkfs.btrfs supports that or needs to be 83 (Linux) ?
>
> FD is for mdraid integrated into the Linux kernel. I have mine at 83.
> It won't hurt to have them at FD, but the kernel will spend extra tim=
e
> as it probes the devices on boot, causing a slight slowdown.

Ok done them id 83 and used 3 devices eventually
Using raid0 for data and metadata
# mkfs.btrfs -m raid0 -d raid0 /dev/sdc1 /dev/sdd2 /dev/sde2

2 SATA and 1 ATA drive
I thought that ATA will bottleneck the other 2 drives but seems like I =
gain
something from it.
Using iozone for benchmark:
# iozone -s 8g -r 1024 -i 0 -i 1
with 2 SATA devices and then 3 devices (SATA + ATA):
        KB  reclen      write   rewrite       read     reread
8388608    1024  134869  139607   229146   228800
8388608    1024  135151  139050   233461   235929

The above is with -o compress option enabled and my cpu topped up on
100% cpu (both cores) while test and copy huge data.
Is it possible I am bottlenecked by my cpu speed?
AMD Opteron 165 @ 2700 Mhz

>>
>> On Thu, Aug 5, 2010 at 3:40 PM, Hubert Kario <hka@qbs.com.pl> wrote:
>>> On Thursday 05 August 2010 16:15:22 Leonidas Spyropoulos wrote:
>>>> Hi all,
>>>>
>>>> I want to make a btrfs raid0 on 2 partitions of my pc.
>>>> Until now I am using the mdadm tools to make a software raid of th=
e 2
>>>> partitions /dev/sde2, /dev/sdd2
>>>> and then mkfs.etx4 the newly created /dev/md0 device.
>>>> From performance point of view is it better to keep the configurat=
ion of
>>>> mdadm and just format the /dev/md0 device as btrfs OR
>>>> delete the raid device and format the 2 partitions /dev/sde2 /dev/=
sdd2
>>>> as a btrfs with 2 devices?
>>>> mkfs.btrfs /dev/sde2 /dev/sdd2
>>>
>>> Btrfs already supports metadata mirroring when the data is striped.=
 What this
>>> means, is while the performance should be more-or-less identical to=
 MD RAID0
>>> (if it isn't it's a bug), your data is a bit more secure as the met=
adata
>>> describing it resides on both drives. Later on it will be possible =
to selct
>>> which directories/files should have what level of redundancy. This =
will allow
>>> to have ~/work RAID1-ed and ~/videos RAID0-ed while keeping both di=
rectories
>>> on the same partition and filesystem.
>>>
>>>> On a sidenote:
>>>> If I decide to go for raid5 which is not supported currently from =
mkfs
>>>> I have to use the mdadm tool anyway, right?
>>>
>>> yes, RAID5 code is not in trunk yet.
>>>
>>> --
>>> Hubert Kario
>>> QBS - Quality Business Software
>>> 02-656 Warszawa, ul. Ksawer=F3w 30/85
>>> tel. +48 (22) 646-61-51, 646-74-24
>>> www.qbs.com.pl
>>>
>>
>>
>>
>> --
>> Caution: breathing may be hazardous to your health.
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-btrf=
s" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at =A0http://vger.kernel.org/majordomo-info.html
>>
>
> Regards,
> Sebastian J.
>
> PS. Please try to bottom-post rather than top-post. Here's a link I
> can advise reading for a clarification on why bottom posting is
> essential: http://www.caliburn.nl/topposting.html
>
Thanks for the heads up about bottom-posting.


--=20
Caution: breathing may be hazardous to your health.
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Re: Raid0 with btrfs

[Hubert Kario]

On Saturday 07 of August 2010 00:24:08 Leonidas Spyropoulos wrote:
> On Fri, Aug 6, 2010 at 7:32 PM, Sebastian 'gonX' Jensen
>=20
> <gonx@overclocked.net> wrote:
> > On 6 August 2010 20:23, Leonidas Spyropoulos <artafinde@gmail.com> =
wrote:
> >> Do I have to change the partition ID flag of each partition?
> >> Currently is set to fd (Linux Raid autodetect) for used from mdadm
> >> mkfs.btrfs supports that or needs to be 83 (Linux) ?
> >=20
> > FD is for mdraid integrated into the Linux kernel. I have mine at 8=
3.
> > It won't hurt to have them at FD, but the kernel will spend extra t=
ime
> > as it probes the devices on boot, causing a slight slowdown.
>=20
> Ok done them id 83 and used 3 devices eventually
> Using raid0 for data and metadata
> # mkfs.btrfs -m raid0 -d raid0 /dev/sdc1 /dev/sdd2 /dev/sde2
>=20
> 2 SATA and 1 ATA drive
> I thought that ATA will bottleneck the other 2 drives but seems like =
I gain
> something from it.
> Using iozone for benchmark:
> # iozone -s 8g -r 1024 -i 0 -i 1
> with 2 SATA devices and then 3 devices (SATA + ATA):
>         KB  reclen      write   rewrite       read     reread
> 8388608    1024  134869  139607   229146   228800
> 8388608    1024  135151  139050   233461   235929
>=20
> The above is with -o compress option enabled and my cpu topped up on
> 100% cpu (both cores) while test and copy huge data.
> Is it possible I am bottlenecked by my cpu speed?
> AMD Opteron 165 @ 2700 Mhz

Considering you have 100% CPU usage during the test, it would seem so.

>=20
> >> On Thu, Aug 5, 2010 at 3:40 PM, Hubert Kario <hka@qbs.com.pl> wrot=
e:
> >>> On Thursday 05 August 2010 16:15:22 Leonidas Spyropoulos wrote:
> >>>> Hi all,
> >>>>=20
> >>>> I want to make a btrfs raid0 on 2 partitions of my pc.
> >>>> Until now I am using the mdadm tools to make a software raid of =
the 2
> >>>> partitions /dev/sde2, /dev/sdd2
> >>>> and then mkfs.etx4 the newly created /dev/md0 device.
> >>>> From performance point of view is it better to keep the configur=
ation
> >>>> of mdadm and just format the /dev/md0 device as btrfs OR
> >>>> delete the raid device and format the 2 partitions /dev/sde2 /de=
v/sdd2
> >>>> as a btrfs with 2 devices?
> >>>> mkfs.btrfs /dev/sde2 /dev/sdd2
> >>>=20
> >>> Btrfs already supports metadata mirroring when the data is stripe=
d.
> >>> What this means, is while the performance should be more-or-less
> >>> identical to MD RAID0 (if it isn't it's a bug), your data is a bi=
t
> >>> more secure as the metadata describing it resides on both drives.
> >>> Later on it will be possible to selct which directories/files sho=
uld
> >>> have what level of redundancy. This will allow to have ~/work RAI=
D1-ed
> >>> and ~/videos RAID0-ed while keeping both directories on the same
> >>> partition and filesystem.
> >>>=20
> >>>> On a sidenote:
> >>>> If I decide to go for raid5 which is not supported currently fro=
m mkfs
> >>>> I have to use the mdadm tool anyway, right?
> >>>=20
> >>> yes, RAID5 code is not in trunk yet.
> >>>=20
> >>> --
> >>> Hubert Kario
> >>> QBS - Quality Business Software
> >>> 02-656 Warszawa, ul. Ksawer=F3w 30/85
> >>> tel. +48 (22) 646-61-51, 646-74-24
> >>> www.qbs.com.pl
> >>=20
> >> --
> >> Caution: breathing may be hazardous to your health.
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe linux-bt=
rfs"
> >> in the body of a message to majordomo@vger.kernel.org
> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >=20
> > Regards,
> > Sebastian J.
> >=20
> > PS. Please try to bottom-post rather than top-post. Here's a link I
> > can advise reading for a clarification on why bottom posting is
> > essential: http://www.caliburn.nl/topposting.html
>=20
> Thanks for the heads up about bottom-posting.

--=20
Hubert Kario
QBS - Quality Business Software
02-656 Warszawa, ul. Ksawer=F3w 30/85
tel. +48 (22) 646-61-51, 646-74-24
www.qbs.com.pl
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" =
in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: Raid0 with btrfs

[Sebastian 'gonX' Jensen]

On 7 August 2010 00:24, Leonidas Spyropoulos <artafinde@gmail.com> wrot=
e:
> On Fri, Aug 6, 2010 at 7:32 PM, Sebastian 'gonX' Jensen
> <gonx@overclocked.net> wrote:
>> On 6 August 2010 20:23, Leonidas Spyropoulos <artafinde@gmail.com> w=
rote:
>>> Do I have to change the partition ID flag of each partition?
>>> Currently is set to fd (Linux Raid autodetect) for used from mdadm
>>> mkfs.btrfs supports that or needs to be 83 (Linux) ?
>>
>> FD is for mdraid integrated into the Linux kernel. I have mine at 83=
=2E
>> It won't hurt to have them at FD, but the kernel will spend extra ti=
me
>> as it probes the devices on boot, causing a slight slowdown.
>
> Ok done them id 83 and used 3 devices eventually
> Using raid0 for data and metadata
> # mkfs.btrfs -m raid0 -d raid0 /dev/sdc1 /dev/sdd2 /dev/sde2
>
> 2 SATA and 1 ATA drive
> I thought that ATA will bottleneck the other 2 drives but seems like =
I gain
> something from it.
> Using iozone for benchmark:
> # iozone -s 8g -r 1024 -i 0 -i 1
> with 2 SATA devices and then 3 devices (SATA + ATA):
> =C2=A0 =C2=A0 =C2=A0 =C2=A0KB =C2=A0reclen =C2=A0 =C2=A0 =C2=A0write =
=C2=A0 rewrite =C2=A0 =C2=A0 =C2=A0 read =C2=A0 =C2=A0 reread
> 8388608 =C2=A0 =C2=A01024 =C2=A0134869 =C2=A0139607 =C2=A0 229146 =C2=
=A0 228800
> 8388608 =C2=A0 =C2=A01024 =C2=A0135151 =C2=A0139050 =C2=A0 233461 =C2=
=A0 235929
>
> The above is with -o compress option enabled and my cpu topped up on
> 100% cpu (both cores) while test and copy huge data.
> Is it possible I am bottlenecked by my cpu speed?
> AMD Opteron 165 @ 2700 Mhz
>
>>>
>>> On Thu, Aug 5, 2010 at 3:40 PM, Hubert Kario <hka@qbs.com.pl> wrote=
:
>>>> On Thursday 05 August 2010 16:15:22 Leonidas Spyropoulos wrote:
>>>>> Hi all,
>>>>>
>>>>> I want to make a btrfs raid0 on 2 partitions of my pc.
>>>>> Until now I am using the mdadm tools to make a software raid of t=
he 2
>>>>> partitions /dev/sde2, /dev/sdd2
>>>>> and then mkfs.etx4 the newly created /dev/md0 device.
>>>>> From performance point of view is it better to keep the configura=
tion of
>>>>> mdadm and just format the /dev/md0 device as btrfs OR
>>>>> delete the raid device and format the 2 partitions /dev/sde2 /dev=
/sdd2
>>>>> as a btrfs with 2 devices?
>>>>> mkfs.btrfs /dev/sde2 /dev/sdd2
>>>>
>>>> Btrfs already supports metadata mirroring when the data is striped=
=2E What this
>>>> means, is while the performance should be more-or-less identical t=
o MD RAID0
>>>> (if it isn't it's a bug), your data is a bit more secure as the me=
tadata
>>>> describing it resides on both drives. Later on it will be possible=
 to selct
>>>> which directories/files should have what level of redundancy. This=
 will allow
>>>> to have ~/work RAID1-ed and ~/videos RAID0-ed while keeping both d=
irectories
>>>> on the same partition and filesystem.
>>>>
>>>>> On a sidenote:
>>>>> If I decide to go for raid5 which is not supported currently from=
 mkfs
>>>>> I have to use the mdadm tool anyway, right?
>>>>
>>>> yes, RAID5 code is not in trunk yet.
>>>>
>>>> --
>>>> Hubert Kario
>>>> QBS - Quality Business Software
>>>> 02-656 Warszawa, ul. Ksawer=C3=B3w 30/85
>>>> tel. +48 (22) 646-61-51, 646-74-24
>>>> www.qbs.com.pl
>>>>
>>>
>>>
>>>
>>> --
>>> Caution: breathing may be hazardous to your health.
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-btr=
fs" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at =C2=A0http://vger.kernel.org/majordomo-info.=
html
>>>
>>
>> Regards,
>> Sebastian J.
>>
>> PS. Please try to bottom-post rather than top-post. Here's a link I
>> can advise reading for a clarification on why bottom posting is
>> essential: http://www.caliburn.nl/topposting.html
>>
> Thanks for the heads up about bottom-posting.
>
>
> --
> Caution: breathing may be hazardous to your health.
>

It seems odd that you are reaching 100% CPU usage. Maybe it's because
I am on an Intel processor with the integrated crc32c module, but with
metadata and data striping on 2 decent desktop drives (60 MB/s in avg
each on large reads), I don't go much anywhere near 10% CPU usage, and
I have compress-force enabled. I've never tried a stress test iozone,
but if I can still remember it, I will try to run it once I get back
from holidays. Sorry that it doesn't help your problem, but it seems
like it's something else.

I'm assuming you're running the nForce4 chipset. I don't recall it
being there, but is there an AHCI option for S-ATA in the BIOS, rather
than legacy or PATA mode, or something in the lines of that? That
could in theory reduce CPU usage somewhat, but shouldn't really affect
anything before very high transfer speeds.

And yes, you are bottlenecked if you're running at max CPU usage. I
would try disabling the compress mount option if the above does not
help.

Regards,
Sebastian J.
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Re: Raid0 with btrfs

[Leonidas Spyropoulos]

On Sat, Aug 7, 2010 at 1:03 AM, Sebastian 'gonX' Jensen
<gonx@overclocked.net> wrote:
> On 7 August 2010 00:24, Leonidas Spyropoulos <artafinde@gmail.com> wr=
ote:
>> On Fri, Aug 6, 2010 at 7:32 PM, Sebastian 'gonX' Jensen
>> <gonx@overclocked.net> wrote:
>>> On 6 August 2010 20:23, Leonidas Spyropoulos <artafinde@gmail.com> =
wrote:
>>>> Do I have to change the partition ID flag of each partition?
>>>> Currently is set to fd (Linux Raid autodetect) for used from mdadm
>>>> mkfs.btrfs supports that or needs to be 83 (Linux) ?
>>>
>>> FD is for mdraid integrated into the Linux kernel. I have mine at 8=
3.
>>> It won't hurt to have them at FD, but the kernel will spend extra t=
ime
>>> as it probes the devices on boot, causing a slight slowdown.
>>
>> Ok done them id 83 and used 3 devices eventually
>> Using raid0 for data and metadata
>> # mkfs.btrfs -m raid0 -d raid0 /dev/sdc1 /dev/sdd2 /dev/sde2
>>
>> 2 SATA and 1 ATA drive
>> I thought that ATA will bottleneck the other 2 drives but seems like=
 I gain
>> something from it.
>> Using iozone for benchmark:
>> # iozone -s 8g -r 1024 -i 0 -i 1
>> with 2 SATA devices and then 3 devices (SATA + ATA):
>> =A0 =A0 =A0 =A0KB =A0reclen =A0 =A0 =A0write =A0 rewrite =A0 =A0 =A0=
 read =A0 =A0 reread
>> 8388608 =A0 =A01024 =A0134869 =A0139607 =A0 229146 =A0 228800
>> 8388608 =A0 =A01024 =A0135151 =A0139050 =A0 233461 =A0 235929
>>
>> The above is with -o compress option enabled and my cpu topped up on
>> 100% cpu (both cores) while test and copy huge data.
>> Is it possible I am bottlenecked by my cpu speed?
>> AMD Opteron 165 @ 2700 Mhz
>>
>>>>
>>>> On Thu, Aug 5, 2010 at 3:40 PM, Hubert Kario <hka@qbs.com.pl> wrot=
e:
>>>>> On Thursday 05 August 2010 16:15:22 Leonidas Spyropoulos wrote:
>>>>>> Hi all,
>>>>>>
>>>>>> I want to make a btrfs raid0 on 2 partitions of my pc.
>>>>>> Until now I am using the mdadm tools to make a software raid of =
the 2
>>>>>> partitions /dev/sde2, /dev/sdd2
>>>>>> and then mkfs.etx4 the newly created /dev/md0 device.
>>>>>> From performance point of view is it better to keep the configur=
ation of
>>>>>> mdadm and just format the /dev/md0 device as btrfs OR
>>>>>> delete the raid device and format the 2 partitions /dev/sde2 /de=
v/sdd2
>>>>>> as a btrfs with 2 devices?
>>>>>> mkfs.btrfs /dev/sde2 /dev/sdd2
>>>>>
>>>>> Btrfs already supports metadata mirroring when the data is stripe=
d. What this
>>>>> means, is while the performance should be more-or-less identical =
to MD RAID0
>>>>> (if it isn't it's a bug), your data is a bit more secure as the m=
etadata
>>>>> describing it resides on both drives. Later on it will be possibl=
e to selct
>>>>> which directories/files should have what level of redundancy. Thi=
s will allow
>>>>> to have ~/work RAID1-ed and ~/videos RAID0-ed while keeping both =
directories
>>>>> on the same partition and filesystem.
>>>>>
>>>>>> On a sidenote:
>>>>>> If I decide to go for raid5 which is not supported currently fro=
m mkfs
>>>>>> I have to use the mdadm tool anyway, right?
>>>>>
>>>>> yes, RAID5 code is not in trunk yet.
>>>>>
>>>>> --
>>>>> Hubert Kario
>>>>> QBS - Quality Business Software
>>>>> 02-656 Warszawa, ul. Ksawer=F3w 30/85
>>>>> tel. +48 (22) 646-61-51, 646-74-24
>>>>> www.qbs.com.pl
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Caution: breathing may be hazardous to your health.
>>>> --
>>>> To unsubscribe from this list: send the line "unsubscribe linux-bt=
rfs" in
>>>> the body of a message to majordomo@vger.kernel.org
>>>> More majordomo info at =A0http://vger.kernel.org/majordomo-info.ht=
ml
>>>>
>>>
>>> Regards,
>>> Sebastian J.
>>>
>>> PS. Please try to bottom-post rather than top-post. Here's a link I
>>> can advise reading for a clarification on why bottom posting is
>>> essential: http://www.caliburn.nl/topposting.html
>>>
>> Thanks for the heads up about bottom-posting.
>>
>>
>> --
>> Caution: breathing may be hazardous to your health.
>>
>
> It seems odd that you are reaching 100% CPU usage. Maybe it's because
> I am on an Intel processor with the integrated crc32c module, but wit=
h
> metadata and data striping on 2 decent desktop drives (60 MB/s in avg
> each on large reads), I don't go much anywhere near 10% CPU usage, an=
d
> I have compress-force enabled. I've never tried a stress test iozone,
> but if I can still remember it, I will try to run it once I get back
> from holidays. Sorry that it doesn't help your problem, but it seems
> like it's something else.

I really doubt my old Opteron has SSE 4.2 and as mentioned from other
users it makes a huge difference.
>
> I'm assuming you're running the nForce4 chipset. I don't recall it
> being there, but is there an AHCI option for S-ATA in the BIOS, rathe=
r
> than legacy or PATA mode, or something in the lines of that? That
> could in theory reduce CPU usage somewhat, but shouldn't really affec=
t
> anything before very high transfer speeds.
>
Yes it's an nForce4 chipset (DFI Expert)
And if I recall it's SATA+PATA mode enabled on mine now.
I can't be sure since I am working on it from ssh.

> And yes, you are bottlenecked if you're running at max CPU usage. I
> would try disabling the compress mount option if the above does not
> help.
After disabling the compress and done the test again it affected the wr=
ite speed
and my CPU wasn't topped up all the time something like 80-90%
results with iozone
        KB   reclen     write   rewrite       read     reread
8388608    1024  147736  147062   135427   134744

thanks for that
>
> Regards,
> Sebastian J.
>

The next step is remove the ATA drive and test again with and without
compress mount.


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Re: Raid0 with btrfs

[Leonidas Spyropoulos]

On Sat, Aug 7, 2010 at 12:16 PM, Leonidas Spyropoulos
<artafinde@gmail.com> wrote:
> On Sat, Aug 7, 2010 at 1:03 AM, Sebastian 'gonX' Jensen
> <gonx@overclocked.net> wrote:
>> On 7 August 2010 00:24, Leonidas Spyropoulos <artafinde@gmail.com> w=
rote:
>>> On Fri, Aug 6, 2010 at 7:32 PM, Sebastian 'gonX' Jensen
>>> <gonx@overclocked.net> wrote:
>>>> On 6 August 2010 20:23, Leonidas Spyropoulos <artafinde@gmail.com>=
 wrote:
>>>>> Do I have to change the partition ID flag of each partition?
>>>>> Currently is set to fd (Linux Raid autodetect) for used from mdad=
m
>>>>> mkfs.btrfs supports that or needs to be 83 (Linux) ?
>>>>
>>>> FD is for mdraid integrated into the Linux kernel. I have mine at =
83.
>>>> It won't hurt to have them at FD, but the kernel will spend extra =
time
>>>> as it probes the devices on boot, causing a slight slowdown.
>>>
>>> Ok done them id 83 and used 3 devices eventually
>>> Using raid0 for data and metadata
>>> # mkfs.btrfs -m raid0 -d raid0 /dev/sdc1 /dev/sdd2 /dev/sde2
>>>
>>> 2 SATA and 1 ATA drive
>>> I thought that ATA will bottleneck the other 2 drives but seems lik=
e I gain
>>> something from it.
>>> Using iozone for benchmark:
>>> # iozone -s 8g -r 1024 -i 0 -i 1
>>> with 2 SATA devices and then 3 devices (SATA + ATA):
>>> =A0 =A0 =A0 =A0KB =A0reclen =A0 =A0 =A0write =A0 rewrite =A0 =A0 =A0=
 read =A0 =A0 reread
>>> 8388608 =A0 =A01024 =A0134869 =A0139607 =A0 229146 =A0 228800
>>> 8388608 =A0 =A01024 =A0135151 =A0139050 =A0 233461 =A0 235929
>>>
>>> The above is with -o compress option enabled and my cpu topped up o=
n
>>> 100% cpu (both cores) while test and copy huge data.
>>> Is it possible I am bottlenecked by my cpu speed?
>>> AMD Opteron 165 @ 2700 Mhz
>>>
>>>>>
>>>>> On Thu, Aug 5, 2010 at 3:40 PM, Hubert Kario <hka@qbs.com.pl> wro=
te:
>>>>>> On Thursday 05 August 2010 16:15:22 Leonidas Spyropoulos wrote:
>>>>>>> Hi all,
>>>>>>>
>>>>>>> I want to make a btrfs raid0 on 2 partitions of my pc.
>>>>>>> Until now I am using the mdadm tools to make a software raid of=
 the 2
>>>>>>> partitions /dev/sde2, /dev/sdd2
>>>>>>> and then mkfs.etx4 the newly created /dev/md0 device.
>>>>>>> From performance point of view is it better to keep the configu=
ration of
>>>>>>> mdadm and just format the /dev/md0 device as btrfs OR
>>>>>>> delete the raid device and format the 2 partitions /dev/sde2 /d=
ev/sdd2
>>>>>>> as a btrfs with 2 devices?
>>>>>>> mkfs.btrfs /dev/sde2 /dev/sdd2
>>>>>>
>>>>>> Btrfs already supports metadata mirroring when the data is strip=
ed. What this
>>>>>> means, is while the performance should be more-or-less identical=
 to MD RAID0
>>>>>> (if it isn't it's a bug), your data is a bit more secure as the =
metadata
>>>>>> describing it resides on both drives. Later on it will be possib=
le to selct
>>>>>> which directories/files should have what level of redundancy. Th=
is will allow
>>>>>> to have ~/work RAID1-ed and ~/videos RAID0-ed while keeping both=
 directories
>>>>>> on the same partition and filesystem.
>>>>>>
>>>>>>> On a sidenote:
>>>>>>> If I decide to go for raid5 which is not supported currently fr=
om mkfs
>>>>>>> I have to use the mdadm tool anyway, right?
>>>>>>
>>>>>> yes, RAID5 code is not in trunk yet.
>>>>>>
>>>>>> --
>>>>>> Hubert Kario
>>>>>> QBS - Quality Business Software
>>>>>> 02-656 Warszawa, ul. Ksawer=F3w 30/85
>>>>>> tel. +48 (22) 646-61-51, 646-74-24
>>>>>> www.qbs.com.pl
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Caution: breathing may be hazardous to your health.
>>>>> --
>>>>> To unsubscribe from this list: send the line "unsubscribe linux-b=
trfs" in
>>>>> the body of a message to majordomo@vger.kernel.org
>>>>> More majordomo info at =A0http://vger.kernel.org/majordomo-info.h=
tml
>>>>>
>>>>
>>>> Regards,
>>>> Sebastian J.
>>>>
>>>> PS. Please try to bottom-post rather than top-post. Here's a link =
I
>>>> can advise reading for a clarification on why bottom posting is
>>>> essential: http://www.caliburn.nl/topposting.html
>>>>
>>> Thanks for the heads up about bottom-posting.
>>>
>>>
>>> --
>>> Caution: breathing may be hazardous to your health.
>>>
>>
>> It seems odd that you are reaching 100% CPU usage. Maybe it's becaus=
e
>> I am on an Intel processor with the integrated crc32c module, but wi=
th
>> metadata and data striping on 2 decent desktop drives (60 MB/s in av=
g
>> each on large reads), I don't go much anywhere near 10% CPU usage, a=
nd
>> I have compress-force enabled. I've never tried a stress test iozone=
,
>> but if I can still remember it, I will try to run it once I get back
>> from holidays. Sorry that it doesn't help your problem, but it seems
>> like it's something else.
>
> I really doubt my old Opteron has SSE 4.2 and as mentioned from other
> users it makes a huge difference.
>>
>> I'm assuming you're running the nForce4 chipset. I don't recall it
>> being there, but is there an AHCI option for S-ATA in the BIOS, rath=
er
>> than legacy or PATA mode, or something in the lines of that? That
>> could in theory reduce CPU usage somewhat, but shouldn't really affe=
ct
>> anything before very high transfer speeds.
>>
> Yes it's an nForce4 chipset (DFI Expert)
> And if I recall it's SATA+PATA mode enabled on mine now.
> I can't be sure since I am working on it from ssh.
>
>> And yes, you are bottlenecked if you're running at max CPU usage. I
>> would try disabling the compress mount option if the above does not
>> help.
> After disabling the compress and done the test again it affected the =
write speed
> and my CPU wasn't topped up all the time something like 80-90%
> results with iozone
> =A0 =A0 =A0 =A0KB =A0 reclen =A0 =A0 write =A0 rewrite =A0 =A0 =A0 re=
ad =A0 =A0 reread
> 8388608 =A0 =A01024 =A0147736 =A0147062 =A0 135427 =A0 134744
>
> thanks for that

I am trying to get the best ration from CPU usage and performance
I found out that 2 SATA devices or 2 SATA and 1 ATA devices does
not make a lot of difference in performance point of view but some in
CPU usage

The iozone results for 2 sata devices with compress are
        KB  reclen      write   rewrite       read     reread
8388608    1024  138133  135645   166751   164077

and the cpu average topped up at ~100%
Avg: 0.2% sy: 76.9% ni: 0.0% hi: 0.0% sy: 1.4% wa: 18.6%

On a side note what are the differences of sy: and wa: cpu on cpu usage=
?
Because on 2 sata + 1 ata the sy value was almost all time under 20%
and wa value was topped till ~85%

What is better? from cpu usage point of view?
=46rom performance point of view I would probably keep something
that gives me around ~130mb/sec write and ~140mb/sec
>>
>> Regards,
>> Sebastian J.
>>
>
> The next step is remove the ATA drive and test again with and without
> compress mount.
>
>
> --
> Caution: breathing may be hazardous to your health.
>



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