[linux-lvm] Raid 10 and LVM stripe

[linux-lvm] Raid 10 and LVM stripe

[Fabricio Archanjo]

Hey all,
I've made a storage by myself.
This box has 24x 1,5T SATA II disks, 3 controllers 3ware PCI-Express,
6G ram memory DDR3 1333Mhz. This disks are distributed for each
controller, 8 disks for each one.  I've done at each controller Raid
10 with 256k stripe size, then I'

[linux-lvm] Raid 10 and LVM stripe

[Fabricio Archanjo]

Hey all,
I've made a storage by myself.
This box has 24x 1,5T SATA II disks, 3 controllers 3ware
PCI-Express,6G ram memory DDR3 1333Mhz. This disks are distributed for
each controller, 8 disks for each one.  I've done at each controller
Raid 10 with 256k stripe size, then I've created one volume group with
all disks and I've created one logical volume with 10G, 3 stripes and
256k of stripe size. I've gotten a great result with it, but i'd like
to know what all think about it.

Sorry my last e-mail, I'm falling asleep and i've sent  unintentionally.


Thanks all,
Fabricio

Re: [linux-lvm] Raid 10 and LVM stripe

[Christopher Cox]

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For a home grown setup, it sounds ok.

8 disks on a controller might be too many... depends.  Obviously, a LOT of
standalone subystems have FAR  fewer controllers.

I would think you'd get some pretty nice numbers off of it.  Would you
consider getting yourself setup on the Phoronix Test Suite (run the disk
benchmark)?  I wouldn't also mind seeing some bonnie++ benchmarks (make
sure you include the version you used).

Your RAID 10.... how did you create that?  Is that somehow coordinated
using the 3ware RAID driver only.... or combination of 3ware RAID level
plus Linux md?  Just curious.

Also... (just thinking out loud)... this box might want more memory.
Again, it depends on how/what the storage is being used for.  For example,
if this were to become a NAS box on a 10Gbit network, performance could go
way up with more memory.  Post some benchies... would love to see them.

Oh.. have you simulated a drive failure yet?  A multi-drive RAID 10
failure?  I think those are good tests.... just to make sure you really
have a workable RAID10 on your hands.



From:	Fabricio Archanjo <farchanjo@gmail.com>
To:	LVM general discussion and development <linux-lvm@redhat.com>
Date:	10/21/2010 12:30 AM
Subject:	[linux-lvm] Raid 10 and LVM stripe
Sent by:	linux-lvm-bounces@redhat.com



Hey all,
I've made a storage by myself.
This box has 24x 1,5T SATA II disks, 3 controllers 3ware
PCI-Express,6G ram memory DDR3 1333Mhz. This disks are distributed for
each controller, 8 disks for each one.  I've done at each controller
Raid 10 with 256k stripe size, then I've created one volume group with
all disks and I've created one logical volume with 10G, 3 stripes and
256k of stripe size. I've gotten a great result with it, but i'd like
to know what all think about it.

Sorry my last e-mail, I'm falling asleep and i've sent  unintentionally.


Thanks all,
Fabricio

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Re: [linux-lvm] Raid 10 and LVM stripe

[Stuart D. Gathman]

On Thu, 21 Oct 2010, Fabricio Archanjo wrote:

> This box has 24x 1,5T SATA II disks, 3 controllers 3ware
> PCI-Express,6G ram memory DDR3 1333Mhz. This disks are distributed for
> each controller, 8 disks for each one.  I've done at each controller
> Raid 10 with 256k stripe size, then I've created one volume group with
> all disks and I've created one logical volume with 10G, 3 stripes and
> 256k of stripe size. I've gotten a great result with it, but i'd like
> to know what all think about it.

I didn't know that "raid 10" was shorthand for "raid 1+0".  While looking 
it up on Wikipedia, I learned about some cool features of the linux md
driver - it can stripe sequential blocks across drives, while still keeping 2 
copies on different drives, even with only 2 drives (what this poor man
usually has).  There is a "near" configuration, where copies of a block are
near each other, and a "far" configuration, where copies of a block are
on the second half (or third...) of each leg.

http://en.wikipedia.org/wiki/Non-standard_RAID_levels#Linux_MD_RAID_10

This gives many benefits of raid 10 with far fewer drives.

-- 
	      Stuart D. Gathman <stuart@bmsi.com>
    Business Management Systems Inc.  Phone: 703 591-0911 Fax: 703 591-6154
"Confutatis maledictis, flammis acribus addictis" - background song for
a Microsoft sponsored "Where do you want to go from here?" commercial.