[linux-lvm] JFS or XFS

[linux-lvm] JFS or XFS

[Rajesh Saxena]

Greetings list..... I am a new user to LVM running kernel 2.4.21 and
lvm 1.0.7
I have a brief question because I am used to ext2 and not new
journaling 
filesystems. Which would you recommend to use on a file mail or web
server:
JFS or XFS and why? Please include your personal experience with the 
filesystems. Thank you so much.

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Re: [linux-lvm] JFS or XFS

[neuron]

reiserfs, guaranteed personally.  Especially on a mail server.
I've used jfs, I crashed it twice on purpose (network swap, then disable network card), both times jfs failed to boot.  (this is because it trusts it's own journal, which a lot of people love about it, both times for me it was wrong..)
Personally I haven't had any problems with XFS though, but I haven't used it that much.

> Greetings list..... I am a new user to LVM running kernel 2.4.21 and
> lvm 1.0.7
> I have a brief question because I am used to ext2 and not new
> journaling 
> filesystems. Which would you recommend to use on a file mail or web
> server:
> JFS or XFS and why? Please include your personal experience with the 
> filesystems. Thank you so much.
> 
> ______________________________________________________________________ 
> Post your free ad now! http://personals.yahoo.ca
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@sistina.com
> http://lists.sistina.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
> 

Re: [linux-lvm] JFS or XFS

[Austin Gonyou]

On Thu, 2004-01-15 at 17:22, neuron wrote:
> reiserfs, guaranteed personally.  Especially on a mail server.
> I've used jfs, I crashed it twice on purpose (network swap, then
> disable network card), both times jfs failed to boot.  (this is
> because it trusts it's own journal, which a lot of people love about
> it, both times for me it was wrong..)
> 
> Personally I haven't had any problems with XFS though, but I haven't
> used it that much.
> 

As a note, any journaling FS that uses metadata for updates will have
issues with server AbEnds where there is data in-flux. The
meta-log(journal) will be in some state of flux and depending on the
timing of the AbEnd, then you can be in trouble. The recent XFS code
finally fixes a lot of issues about this with a meta journal update
daemon and set of sysctls that are configurable. Also, another way to
ensure your journal is safe, both with JFS, XFS, ext3 in full logging
mode, is to put your journal on a separate device that may not be
affected by the AbEnd. I can reveal more, but am short on time. I would
personally ask each list of the FS your interested in after you've read
about each.

It should be noted as well that each journaling FS has it's own issues
which are application dependent. i.e. works better in some cases than
others based on usage patterns, file types, etc.
-- 
Austin Gonyou <austin@coremetrics.com>
Coremetrics, Inc.

Re: [linux-lvm] JFS or XFS

[Greg Freemyer]

On Thu, 2004-01-15 at 18:22, neuron wrote:
> reiserfs, guaranteed personally.  Especially on a mail server.

I agree, reiserfs was tuned for handling lots of small files.  Sounds
perfect for a mail server.

> I've used jfs, I crashed it twice on purpose (network swap, then disable network card), both times jfs failed to boot.  (this is because it trusts it's own journal, which a lot of people love about it, both times for me it was wrong..)
> Personally I haven't had any problems with XFS though, but I haven't used it that much.
> 

If you go with XFS, stay away from anything older than 1.3.1.

The 1.2 and prior releases had this really nice feature that they
ignored the sync command (and fsync I think).

The end result is that with a power outage or kernel lockup you could
lose lots of work.  I had one failure on a lightly used machine that had
a whole days activities still sitting in the OS disk cache when the
kernel locked up.

This is fixed in 1.3.1, 

Greg

Re: [linux-lvm] JFS or XFS

[Spam]

> On Thu, 2004-01-15 at 18:22, neuron wrote:
>> reiserfs, guaranteed personally.  Especially on a mail server.

> I agree, reiserfs was tuned for handling lots of small files.  Sounds
> perfect for a mail server.

  Also,  ReiserFS  tools  are  very mature when it comes to repair and
  recover  from  damages. I do not know how the JFS/XFS tools are, but
  it  would  be  a good idea to investigate how you can repair your FS
  _if_ you end up with some sort of failure..

>> I've used jfs, I crashed it twice on purpose (network swap,
>> then disable network card), both times jfs failed to boot.  (this
>> is because it trusts it's own journal, which a lot of people love
>> about it, both times for me it was wrong..)
>> Personally I haven't had any problems with XFS though, but I haven't used it that much.
>> 

> If you go with XFS, stay away from anything older than 1.3.1.

> The 1.2 and prior releases had this really nice feature that they
> ignored the sync command (and fsync I think).

> The end result is that with a power outage or kernel lockup you could
> lose lots of work.  I had one failure on a lightly used machine that had
> a whole days activities still sitting in the OS disk cache when the
> kernel locked up.

> This is fixed in 1.3.1, 

> Greg




> _______________________________________________
> linux-lvm mailing list
> linux-lvm@sistina.com
> http://lists.sistina.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

Re: [linux-lvm] JFS or XFS

[Rajesh Saxena]

Thank you all for the replies regarding ReiserFS....... I will have to
do more research into this matter because originally I did not consider
reiser for the server. It is always good to get other peoples opinions
on topics like this. I have one small request if you don't mind. The
mail server will run cyrus imapd and while reading the documentation I
saw the following note which is attached below after my email. The
author of this document also notes that XFS includes a program called
xfs_freeze which will freeze a filesystem from new changes so a more
reliable snapshot can be created. Again people here with more
experience with LVM and reiserfs might know of a better way to do the
snapshot for backups. Any opinions?
Thank you all for your insight. Please keep posting if you have
different opinionss.

Please scroll all the way to the bottom:
http://acs-wiki.andrew.cmu.edu/twiki/bin/view/Cyrus/Backup

One issue you may run into: if you're using ReiserFS, at least on Linux
2.4 with LVM1, then snapshots may occasionally fail. The snapshot will
be created fine, but the ReiserFS fileystem on it will not be mountable
if it has incomplete transactions. The ReiserFS code tries to replay
the transactions, fails because the snapshot is read-only, and fails to
mount the FS. I've found that syncing the disks before taking the
snapshot reduces the chances of this happening dramatically:

sync && sleep 1 && sync && sleep 1 && sync # try to make sure FS will
be clean
nice -n -19 lvcreate -s -L 1G -n var_s /dev/OS/var >&/dev/null || \
  ( echo "Error creating snapshot of /var: $?" && exit 1 )


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Re: [linux-lvm] JFS or XFS

[Austin Gonyou]

On Thu, 2004-01-15 at 17:33, Greg Freemyer wrote: 
> On Thu, 2004-01-15 at 18:22, neuron wrote:
> > reiserfs, guaranteed personally.  Especially on a mail server.
> 
> I agree, reiserfs was tuned for handling lots of small files.  Sounds
> perfect for a mail server.

Many tests prove this to be true as well. Search on google for what
Greg's saying. Lots of benches out there to see. 

[...]

> > Personally I haven't had any problems with XFS though, but I haven't
> used it that much.
> > 
> 
> If you go with XFS, stay away from anything older than 1.3.1.

Not to mention 1.3.x is when the xfslogd and xfsdatad were finally
implemented. I noted this in my prior email regarding tunable log
updates.


> The 1.2 and prior releases had this really nice feature that they
> ignored the sync command (and fsync I think).

It wasn't ignored, just not paid attention too as often it should've
been. ;)

> The end result is that with a power outage or kernel lockup you could
> lose lots of work.  I had one failure on a lightly used machine that
> had
> a whole days activities still sitting in the OS disk cache when the
> kernel locked up.

Depending on how often a system might sync()/fsync() this is true. As
well as any FS options you use for mounting XFS volumes regarding
log-buffers, io buffers, etc. 

> This is fixed in 1.3.1, 
> 
> Greg

Yes, much better now. Still, even with JFS or EXT3, as I noted before,
certain AbEnds will cause meta data to be lost. This is more a function
of hardware caching in a non-backed state, such as large cache buffers
of some drives 8MB drive cache, etc.  (i.e. no battery backed up cache)

-- 
Austin Gonyou <austin@coremetrics.com>
Coremetrics, Inc.

Re: [linux-lvm] JFS or XFS

[Heinz Mauelshagen]

On Thu, Jan 15, 2004 at 07:29:08PM -0500, Rajesh Saxena wrote:
> Thank you all for the replies regarding ReiserFS....... I will have to
> do more research into this matter because originally I did not consider
> reiser for the server. It is always good to get other peoples opinions
> on topics like this. I have one small request if you don't mind. The
> mail server will run cyrus imapd and while reading the documentation I
> saw the following note which is attached below after my email. The
> author of this document also notes that XFS includes a program called
> xfs_freeze which will freeze a filesystem from new changes so a more
> reliable snapshot can be created. Again people here with more
> experience with LVM and reiserfs might know of a better way to do the
> snapshot for backups. Any opinions?
> Thank you all for your insight. Please keep posting if you have
> different opinionss.
> 
> Please scroll all the way to the bottom:
> http://acs-wiki.andrew.cmu.edu/twiki/bin/view/Cyrus/Backup
> 
> One issue you may run into: if you're using ReiserFS, at least on Linux
> 2.4 with LVM1, then snapshots may occasionally fail. The snapshot will
> be created fine, but the ReiserFS fileystem on it will not be mountable
> if it has incomplete transactions. The ReiserFS code tries to replay
> the transactions, fails because the snapshot is read-only, and fails to
> mount the FS. I've found that syncing the disks before taking the
> snapshot reduces the chances of this happening dramatically:

Rajesh,

you need to apply the VFS-Lock patch from our web site to avoid your
following 'trick'. That enables LVM to 'flush' all pending fs io
before activating the snapshot.

Another option is to try out LVM2/device-mapper which
supports writable snapshots :)

Regards,
Heinz    -- The LVM Guy --

> 
> sync && sleep 1 && sync && sleep 1 && sync # try to make sure FS will
> be clean
> nice -n -19 lvcreate -s -L 1G -n var_s /dev/OS/var >&/dev/null || \
>   ( echo "Error creating snapshot of /var: $?" && exit 1 )
> 
> 
> ______________________________________________________________________ 
> Post your free ad now! http://personals.yahoo.ca
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@sistina.com
> http://lists.sistina.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

*** Software bugs are stupid.
    Nevertheless it needs not so stupid people to solve them ***

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Re: [linux-lvm] JFS or XFS

[Rajesh Saxena]

 --- Heinz Mauelshagen <mauelshagen@redhat.com> wrote: 

> you need to apply the VFS-Lock patch from our web site to avoid your
> following 'trick'. That enables LVM to 'flush' all pending fs io
> before activating the snapshot.

ok I will have to look into that this weekend. Just to point something
out I am most likely looking in wrong place but I can't find patch for
kernel 2.4.21 here
http://tech.sistina.com/cgi-bin/viewcvs.cgi/LVM/PATCHES/

> Another option is to try out LVM2/device-mapper which
> supports writable snapshots :)

I was under impression that LVM2 and device-mapper are dependant on
kernel 2.6 which I don't feel comfortable using for server. I am
curious which filesystem you prefer with LVM 1 since you are the "The
LVM Guy" =)

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Re: [linux-lvm] JFS or XFS

[Alasdair G Kergon]

On Fri, Jan 16, 2004 at 05:54:19PM -0500, Rajesh Saxena wrote:
> I was under impression that LVM2 and device-mapper are dependant on
> kernel 2.6 which I don't feel comfortable using for server. 

There are device-mapper patches for 2.4 kernels for use with LVM2 tools.

Note that LVM1 snapshots are implemented differently from LVM2 snapshots
so you should drop any LVM1 snapshots before switching to LVM2.

(And Linus's 2.6 tree does not include snapshot support, as this is
still being tested.)

Alasdair
-- 
agk@uk.sistina.com

Re: [linux-lvm] JFS or XFS

[Dan Sully]

* Alasdair G Kergon <agk@uk.sistina.com> shaped the electrons to say...

> There are device-mapper patches for 2.4 kernels for use with LVM2 tools.
> 
> Note that LVM1 snapshots are implemented differently from LVM2 snapshots
> so you should drop any LVM1 snapshots before switching to LVM2.
> 
> (And Linus's 2.6 tree does not include snapshot support, as this is
> still being tested.)

Where can one find 2.6 snapshot patches?

-D
-- 
There is no spoon.

Re: [linux-lvm] JFS or XFS

[Alasdair G Kergon]

On Fri, Jan 16, 2004 at 04:46:54PM -0800, Dan Sully wrote:
> Where can one find 2.6 snapshot patches?
 
http://people.sistina.com/~thornber/dm/index.html

Alasdair
-- 
agk@uk.sistina.com

Re: [linux-lvm] JFS or XFS

[Steven Lembark]

> how you can repair your FS
>   _if_ you end up with some sort of failure..

Suggeest reading it as "_when_". Problem with "_if_" is that
the fix is too often ignoring it.

--
Steven Lembark                               2930 W. Palmer
Workhorse Computing                       Chicago, IL 60647
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