moosefs-users

[Moosefs-users] MFS reports used space

[Stas O. <sta...@gm...>]

Hi.

I've installed MFS chunkservers on two boxes with 4TB each.

For some reason, the MFS shows as 187 GiB already used - while I didn't
place any files there yet, and the chunks number equal to 0.

Any idea why it shows such stats?

Regards.

Re: [Moosefs-users] MFS reports used space

[Michał B. <mic...@ge...>]

Please read this faq entry: 

http://www.moosefs.org/moosefs-faq.html#df

 

Are the disks used exclusively for MooseFS chunks or do you have some other
data there?

 

 

Regards

Michal

 

From: Stas Oskin [mailto:sta...@gm...] 
Sent: Tuesday, July 06, 2010 9:56 AM
To: moo...@li...
Subject: [Moosefs-users] MFS reports used space

 

Hi.

I've installed MFS chunkservers on two boxes with 4TB each.

For some reason, the MFS shows as 187 GiB already used - while I didn't
place any files there yet, and the chunks number equal to 0.

Any idea why it shows such stats?

Regards.

Re: [Moosefs-users] MFS reports used space

[Laurent W. <lw...@hy...>]

On Tue, 6 Jul 2010 10:56:13 +0300
Stas Oskin <sta...@gm...> wrote:

> Hi.
> 
> I've installed MFS chunkservers on two boxes with 4TB each.
> 
> For some reason, the MFS shows as 187 GiB already used - while I didn't
> place any files there yet, and the chunks number equal to 0.
> 
> Any idea why it shows such stats?
I bet it is due to reserved blocks for root.
If you run ext2/3/4 try:
tune2fs -m 0 /dev/bla with ext2/3 tune4fs if ext4.
No need to unmount or put the volume read-only.
Some space will be kept as used, but formatting is taking a bunch of
blocks.
-- 
Laurent Wandrebeck
HYGEOS, Earth Observation Department / Observation de la Terre
Euratechnologies
165 Avenue de Bretagne
59000 Lille, France
tel: +33 3 20 08 24 98
http://www.hygeos.com
GPG fingerprint/Empreinte GPG: F5CA 37A4 6D03 A90C 7A1D  2A62 54E6 EF2C
D17C F64C

Re: [Moosefs-users] MFS reports used space

[Laurent W. <lw...@hy...>]

On Tue, 6 Jul 2010 12:53:37 +0300
Stas Oskin <sta...@gm...> wrote:

> > I bet it is due to reserved blocks for root.
> > If you run ext2/3/4 try:
> > tune2fs -m 0 /dev/bla with ext2/3 tune4fs if ext4.
> > No need to unmount or put the volume read-only.
> > Some space will be kept as used, but formatting is taking a bunch of
> > blocks.
> >
> >
> Yep, that was it, thanks!
> 
> Speaking of ext4, have you tried it with mfs? I seen some bad experience
> posted here about this.
The only mail I found is « I tried it on secondary cluster in ext4 and
btrfs, for 3 months ok, failed after I could not find the reason, »
I'd blame btrfs for sure, as it is still experimental.
I have two boxes whose moosefs volume is ext4, no problem up to now.
Actually, to be more precise, the file which is loop-mounted is stored
on ext4. the FS in the given file is ext3. (yes, yes, testing
deployment for now).
Other than that, I have 2 classical volume of 14TB each running ext4
without a glitch. Yes, they do not run mfs, but as mfs is in
user-space, it can't be blamed for FS problems (which are kernel-space).
Hope it helps.
-- 
Laurent Wandrebeck
HYGEOS, Earth Observation Department / Observation de la Terre
Euratechnologies
165 Avenue de Bretagne
59000 Lille, France
tel: +33 3 20 08 24 98
http://www.hygeos.com
GPG fingerprint/Empreinte GPG: F5CA 37A4 6D03 A90C 7A1D  2A62 54E6 EF2C
D17C F64C

Re: [Moosefs-users] MFS reports used space

[Laurent W. <lw...@hy...>]

On Tue, 6 Jul 2010 15:22:12 +0300
Stas Oskin <sta...@gm...> wrote:

> >
> >
> > Thanks, it helps indeed.
> 
> My concern that us MFS presents additional layer over FS, it would take a
> long time to find out what causing issues, ext4 or MFS.
> Moreover, as Michal says they using ext3 so probably never encountered any
> issues with ext4.
> 
> I'm going to convert a machine to ext4 / xfs (also testing HA in process),
> and benchmark then, and we could share the results.
That would be nice numbers to have, indeed.
> 
> Speaking of, do you know how ext4 compares to xfs, especially for such
> clustered file systems as mfs?
I have no XFS at work these days. I may have some in a couple months,
but nothing sure. All I can say is that XFS is more efficient with big
files than ext* is. I tend to find XFS snappier than ext* in general,
but for deletion operations. Nothing scientifically proved, anyway.
-- 
Laurent Wandrebeck
HYGEOS, Earth Observation Department / Observation de la Terre
Euratechnologies
165 Avenue de Bretagne
59000 Lille, France
tel: +33 3 20 08 24 98
http://www.hygeos.com
GPG fingerprint/Empreinte GPG: F5CA 37A4 6D03 A90C 7A1D  2A62 54E6 EF2C
D17C F64C