Re: [opensuse] XFS Slow When Deleting Large Files

On Mon, Mar 9, 2009 at 11:48 AM, Greg Freemyer wrote:

On Mon, Mar 9, 2009 at 10:25 AM, Randall R Schulz wrote:

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On Monday March 9 2009, Carlos E. R. wrote:

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On Monday, 2009-03-09 at 07:34 -0700, Randall R Schulz wrote:

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Question first (background below): Why does XFS write every sector (formerly) occupied by a file when that file is deleted? If this is some sort of security feature, can it be disabled? This action makes deletion of large files very slow.

Not in my system:

I take it this was a dd command from /dev/zero to a file on an XFS file system?

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35000+0 records in 35000+0 records out 1146880000 bytes (1.1 GB) copied, 16.9719 s, 67.6 MB/s

real 0m17.246s user 0m0.024s sys 0m4.500s

cer@nimrodel:~/tmp> l -h bigfile -rw-r--r-- 1 cer users 1.1G 2009-03-09 15:51 bigfile

cer@nimrodel:~/tmp> time rm bigfile

real 0m0.109s <================================= user 0m0.004s sys 0m0.056s

cer@nimrodel:~/tmp> mount | grep /home /dev/hda11 on /home type xfs (rw,noatime,nodiratime)

I don't suppress atime recording, though it's hard to see how that would relate to large-file deletion time.

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XFS is the fastest filsystem deleting files. Maybe JFS is faster, they say (mythtv docs).

Since this came up, I've done some searching, and what I've found suggests that XFS has particularly _bad_ delete times. I found a page (http://everything2.com/index.pl?node_id=1479435, dated 2003) that details extensive tweaking meant to get XFS delete performance up.

xfs is notoriously slow at deleting small files. I tested deleting a linux kernel source tree a few weeks ago.

I think reiser took a couple seconds. (I may have been testing ext3.)

I know xfs took just over a minute.

For large files, xfs is reputedly very fast.

The dd test above, does not have any "sync" calls, so it may are may not mean anything. ie. The whole thing may have taken place in cache and not even caused any updates on disk. Who knows.

Greg -- Greg Freemyer Litigation Triage Solutions Specialist http://www.linkedin.com/in/gregfreemyer First 99 Days Litigation White Paper - http://www.norcrossgroup.com/forms/whitepapers/99%20Days%20whitepaper.pdf

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Sorry if this is off-topic but I am just wondering what is the special appeal of XFS? Is it the large-file capabilities? Or the alleged higher reliability/restorability in the event of a crash? Boris. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org