On 02/24/2012 01:50 AM, Sabuj Pattanayek wrote:
This seems to be a bug in XFS as Joe pointed out :
http://oss.sgi.com/archives/xfs/2011-06/msg00233.html
This was in a different context though. Are your files sparse by default?
http://stackoverflow.com/questions/6940516/create-sparse-file-with-alternate-data-and-hole-on-ext3-and-xfs
It seems to be there in XFS available natively in RHEL6 and RHEL5
Yes.
On Thu, Feb 23, 2012 at 5:12 PM, Sabuj Pattanayek<[email protected]> wrote:
Hi,
I've been migrating data from an old striped 3.0.x gluster install to
a 3.3 beta install. I copied all the data to a regular XFS partition
(4K blocksize) from the old gluster striped volume and it totaled
9.2TB. With the old setup I used the following option in a "volume
stripe" block in the configuration file in a client :
volume stripe
type cluster/stripe
option block-size 2MB
subvolumes ....
end-volume
IIRC, the data was using up about the same space on the old striped
volume (9.2T) . While copying the data back to the new v3.3 striped
gluster volume on the same 5 servers/same brick filesystems (XFS w/4K
blocksize), I noticed that the amount stored on disk increased by 5x
512B blocks are 1/8 the size of the 4096B blocks, so a scheme where 512B
blocks are naively replaced by 4096B blocks should net an 8x space
change if that is the issue.
.
Currently if I do a du -sh on the gluster fuse mount of the new
striped volume I get 4.3TB (I haven't finished copying all 9.2TB of
data over, stopped it prematurely because it's going to use up all the
physical disk it seems if I let it keep going). However, if I do a du
-sh at the filesystem / brick level on each of the 5 directories on
the 5 servers that store the striped data, it shows that each one is
storing 4.1TB. So basically, 4.3TB of data from a 4K block size FS
took up 20.5TB of storage on a 128KB block size striped gluster
So you have 5 servers, each storing a portion of a stripe. You get a 5x
change in allocation? This sounds less like an xfs issue and more like
a gluster allocation issue. I've not looked lately at the stripe code,
but it may allocate the same space on each node, using the access
pattern for performance.
volume. What is the correlation between the " option block-size"
setting on client configs in cluster/stripe blocks in 3.0.x vs the
cluster.stripe-block-size parameter in 3.3? If these settings are
talking about what I think they mean, then basically a file that is 1M
in size would be written out to the stripe in 128KB chunks across N
servers, i.e. 128/N KB of data per brick? What happens when the stripe
block size isn't evenly divisible by N (e.g. 128/5 = 25.6). If the old
block-size and new stripe-block-size options are describing the same
thing, then wouldn't a 2MB block size from the old config cause more
storage to be used up vs a 128KB block size?
Thanks,
Sabuj
_______________________________________________
Gluster-users mailing list
[email protected]
http://gluster.org/cgi-bin/mailman/listinfo/gluster-users
--
Joseph Landman, Ph.D
Founder and CEO
Scalable Informatics Inc.
email: [email protected]
web : http://scalableinformatics.com
http://scalableinformatics.com/sicluster
phone: +1 734 786 8423 x121
fax : +1 866 888 3112
cell : +1 734 612 4615
_______________________________________________
Gluster-users mailing list
[email protected]
http://gluster.org/cgi-bin/mailman/listinfo/gluster-users
