XFS slow performance

Hi All,

I'm using the UBUNTU server with LVM group of SCSI harddisk.

I'm using this setting for XFS:

1. mkfs.xfs --l logdev=/dev/sda1,size=64m --d agcount=32 /dev/test/department

1. mount -o noatime,nodiratime,nobarrier,logbufs=8 /dev/test/department /data/

My current situation is :

1) I'm using XFS file system as my files server
2) i'm using snapshot to make a hot backup like shadow copies in windows

The problem is it takes a long time and some time it make time out for:

1) New file creation
2) Copy files from xfs shared to another local pc's

** what have i check is; if no snapshot was taken; the files sharing was go on without problem and really fast.
This problem occurred only when we have a snapshot drives. even a single drive.

please help me and advise me on this?

Regards
Rozi

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There's not a lot to go on here, but it sounds like it's possibly an lvm snapshot issue, not an xfs issue, to me. Can you test another filesystem temporarily to see if you see the same slowdown when a snapshot is active?

When a snapshot is active, it's doing copy on write, which will slow things down to some degree.

-Eric

No problem; please keep the list on cc: so that others with similar problems will have something to find on google :)

That's right; xfs itself has no snapshot capability. It's done at the block layer (via lvm in your case).

I don't use snapshots much so can't say, but they do have overhead. You may have more luck asking for suggestions on the lvm users list. There might be some tuning you can do.

-Eric