[Gluster-devel] accessing glusterfs mounted share - really slow

Matthias Albert gluster at linux4experts.de
Fri Aug 31 09:50:18 UTC 2007


Hi,

Anand Avati schrieb:
> Matthias,
>  have you loaded io-threads on the server bricks? io-threads is meant 
> to classify file I/O and metadata operations into seperate threads, 
> thus, readdir() operations would not fall-in-line with ongoing writes, 
> instead gets into a different queue and processed by a seperate 
> thread. this should make ls more 'interactive' while disk I/O is 
> happening.
>
on server side I only do a export of my volumes

#server-side
---snip---
...
volume sdb1
        type storage/posix                  
        option directory /export/sdb1
end-volume

volume sdc1
        type storage/posix 
        option directory /export/sdc1
end-volume

volume server
        type protocol/server
        option transport-type tcp/server
        option listen-port 6997
        subvolumes sdb1 sdc1
        option auth.ip.sdb1.allow *
        option auth.ip.sdc1.allow *
end-volume
...
---snap---

and on client side I added the afr, unify ,writebehind and readahead 
translator.

#client-side
---snip---
...
volume gluster1-sdb1
  type protocol/client
  option transport-type tcp/client
  option remote-host gluster1
  option remote-port 6997
  option remote-subvolume sdb1
end-volume

volume gluster1-sdc1
  type protocol/client
  option transport-type tcp/client
  option remote-host gluster1
  option remote-port 6997
  option remote-subvolume sdc1
end-volume
...
volume afr1
  type cluster/afr
  subvolumes gluster3-hdb1 gluster4-hdc1
  option replicate *:2
end-volume
...
volume cluster
  type cluster/unify
  subvolumes afr1 afr2 afr3 afr4 gluster2-hdb1
  option scheduler alu
  option alu.limits.min-free-disk  6GB
  option alu.limits.max-open-files 10000
  option namespace brick
  option alu.order 
disk-usage:read-usage:write-usage:open-files-usage:disk-speed-usage
  option alu.disk-usage.entry-threshold 100GB
  option alu.disk-usage.exit-threshold  60MB
  option alu.open-files-usage.entry-threshold 1024
  option alu.open-files-usage.exit-threshold 32
  option alu.stat-refresh.interval 10sec
end-volume

volume writebehind
  type performance/write-behind
  option aggregate-size 131072 # unit in bytes
  option flush-behind off
  subvolumes cluster
end-volume

volume readahead
  type performance/read-ahead
  option page-size 65536    
  option page-count 16
  subvolumes writebehind
end-volume
---snap---

So I guess, I should add a readahead and writebehind translator on 
server side?

Regards,

  Matthias

> avati
>
> 2007/8/31, Matthias Albert <gluster at linux4experts.de 
> <mailto:gluster at linux4experts.de>>:
>
>     Hi Krishna,
>
>
>     Krishna Srinivas schrieb:
>     > Hi Matthias,
>     >
>     > If I understand correctly, for you all the operations are fine, but
>     > when a "cp" is being done and simultaneously you do "ls" from
>     > another client, the "ls" is slow?
>     >
>     yepp, absolutly correct. Only If I do a "cp or dd for example" the
>     ls or
>     tab completion is really slow and only in the glusterfs mounted share.
>
>     Matthias
>
>     > Krishna
>     >
>     > On 8/31/07, Matthias Albert <gluster at linux4experts.de
>     <mailto:gluster at linux4experts.de>> wrote:
>     >
>     >> Hi all,
>     >>
>     >> first of all, I've to say that gluterfs is really cool and
>     absolutly
>     >> great. I'm not a cluster filesystem specialist but I
>     tested/configured
>     >> openafs and lustre and both of them are so huge and complicated.
>     >> As I saw glusterfs and played a little bit with it, I was really
>     >> surprised how easy it is to setup a cluster filesystem without
>     extra
>     >> acl's, without formatting the new filesystem without a
>     >> metadata/objectserver :-). Thanks a lot for this.
>     >>
>     >> Of course I've some questions :-).
>     >>
>     >> I've setup 4 glusterfsd server, each of them with a storage of
>     about
>     >> 400-500 Gig pre-tax.
>     >> On client side  I made different afr's over my remote volumes and
>     >> finally a unify over the afr's. Readahead and writebehind is
>     also enabled.
>     >>
>     >> Everything is working fine. I can copy "tons" of Gigabytes in my
>     >> glusterfs without any problms and also my performance is
>     absolutly great.
>     >>
>     >> But every time I start a "cp" or do a "dd test (to write some
>     testfiles
>     >> in the gluster storage) on some of my clients (I've 3 glusterfs
>     clients
>     >> one of them is a bacula server which uses the glusterfs as
>     storage)
>     >> all access from my glusterfs clients to the mounted share is really
>     >> slow. It takes sometimes about 3-4 seconds till my ls is
>     printing the
>     >> output of the directory.
>     >>
>     >> e.g.
>     >> ---snip---
>     >> bash# df -h
>     >> glusterfs             892G   84G  809G  10% /backup
>     >>
>     >> gsx:/backup/vmware-images # time ll
>     >> ...
>     >> ...
>     >> real     0m2.863s
>     >> user    0m0.004s
>     >> sys     0m0.005s
>     >> gsx:/backup/vmware-images #
>     >> ---snap---
>     >>
>     >> Also the "tab completion" in the mounted glusterfs share is
>     really slow.
>     >> Access of not mounted glusterfs share is just normal (accessing
>     /etc
>     >> /usr/ /root etc. )
>     >>
>     >> Does anyone know these "phenomenon"?
>     >>
>     >> I'm using Debian as distro for all of my servers and Debian and
>     SuSE on
>     >> Client side.
>     >>
>     >> glusterfs version: glusterfs--mainline--2.5 patch-459
>     >> fuse: fuse-2.7.0-glfs3
>     >>
>     >> If needed I can post my configs, strace outputs of ls -la and
>     so on.
>     >>
>     >> Regards,
>     >>
>     >>   Matthias
>     >>
>     >>
>     >>
>     >>
>     >>
>     >>
>     >>
>     >>
>     >>
>     >>
>     >>
>     >>
>     >> _______________________________________________
>     >> Gluster-devel mailing list
>     >> Gluster-devel at nongnu.org <mailto:Gluster-devel at nongnu.org>
>     >> http://lists.nongnu.org/mailman/listinfo/gluster-devel
>     <http://lists.nongnu.org/mailman/listinfo/gluster-devel>
>     >>
>     >>
>
>
>
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>
>
>
> -- 
> It always takes longer than you expect, even when you take into 
> account Hofstadter's Law.
>
> -- Hofstadter's Law 






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