[CentOS] GFS and Small Files

[Marc Grimme]

Hi,
independently from the results you have seen it might be always reasonable to 
tune a gfs filesystem as follows:
http://kbase.redhat.com/faq/docs/DOC-6533
specially
mount with noatime and
gfs_tool settune <fs> glock_purge 50

Regards Marc.
On Wednesday 29 April 2009 13:01:17 Hairul Ikmal Mohamad Fuzi wrote:
> Hi all,
>
> We are running CentOS 5.2 64bit as our file server.
> Currently, we used GFS (with CLVM underneath it) as our filesystem
> (for our multiple 2TB SAN volume exports) since we plan to add more
> file servers (serving the same contents) later on.
>
> The issue we are facing at the moment is we found out that command
> such as 'ls' gives a very slow response.(e.g 3-4minutes for the
> outputs of ls to be printed out, or in certain cases, 20minutes or so)
> This is completely true especially in directories containing "large
> number" of small files (e.g 90000+ of 1-4kb files). The thing is, most
> of system users are generating these small files frequently as part of
> their workflow.
>
> We tried emulating the same scenario (90000+ of small files) on a ext3
> partition and it gives almost the same result.
>
> I believe most of the CLVM/GFS settings done are using the defaults
> parameters. Additionally, we would prefer to stick to GFS (or at least
> ext3) as it is part of CentOS / RHEL distribution rather than changing
> into other small-files 'friendly' filesystems (such as XFS, ReiserFS).
>
> I'm exploring whether is there anyway we can tune the GFS parameters
> to make the system more responsive?
> I have read that we can apply 'dir_index' option to ext3 partition to
> speedup things, but I'm not so sure about GFS.
>
> Below are the output from "gfs_tool gettune /export/gfs" :
>
> ilimit1 = 100
> ilimit1_tries = 3
> ilimit1_min = 1
> ilimit2 = 500
> ilimit2_tries = 10
> ilimit2_min = 3
> demote_secs = 300
> incore_log_blocks = 1024
> jindex_refresh_secs = 60
> depend_secs = 60
> scand_secs = 5
> recoverd_secs = 60
> logd_secs = 1
> quotad_secs = 5
> inoded_secs = 15
> glock_purge = 0
> quota_simul_sync = 64
> quota_warn_period = 10
> atime_quantum = 3600
> quota_quantum = 60
> quota_scale = 1.0000   (1, 1)
> quota_enforce = 1
> quota_account = 1
> new_files_jdata = 0
> new_files_directio = 0
> max_atomic_write = 4194304
> max_readahead = 262144
> lockdump_size = 131072
> stall_secs = 600
> complain_secs = 10
> reclaim_limit = 5000
> entries_per_readdir = 32
> prefetch_secs = 10
> statfs_slots = 64
> max_mhc = 10000
> greedy_default = 100
> greedy_quantum = 25
> greedy_max = 250
> rgrp_try_threshold = 100
> statfs_fast = 0
>
>
> TIA.
>
> .ikmal
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-- 
Gruss / Regards,

Marc Grimme
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