Hi, Leandro: Thanks for the good reminder. Yes, we did. Any other comments? Best, Jas --- Leandro Dardini <l.dardini@xxxxxxxxxxxxxxx> wrote: > Just remember to disable atime on the GFS volume. If > atime is enabled maybe there is the lock contention > for the writing of this info if multiple clients > "read" the directory. > > Leandro > > > -----Messaggio originale----- > > Da: linux-cluster-bounces@xxxxxxxxxx > > [mailto:linux-cluster-bounces@xxxxxxxxxx] Per > conto di Ja S > > Inviato: venerd?9 maggio 2008 8.38 > > A: linux clustering > > Oggetto: Re: Why GFS is so slow? > What it is > > waiting for? > > > > Hi, Andrew: > > > > Thank you very much for the help. Yes, your > explanation > > really makes sense. I buy it. > > > > But I would like to discuss it a little bit > further. > > The following message was part of my previous > reply to Wendy. > > Just paste it here for your convenience. > > > > > > # stat abc/ > > File: `abc/' > > Size: 8192 Blocks: 6024 IO > Block: > > 4096 directory > > Device: fc00h/64512d Inode: 1065226 Links: > 2 > > Access: (0770/drwxrwx---) Uid: ( 0/ root) > > Gid: ( 0/ root) > > Access: 2008-05-08 06:18:58.000000000 +0000 > > Modify: 2008-04-15 03:02:24.000000000 +0000 > > Change: 2008-04-15 07:11:52.000000000 +0000 > > > > # cd abc/ > > # time ls | wc -l > > 31764 > > > > real 0m44.797s > > user 0m0.189s > > sys 0m2.276s > > > > > > >From the test results, it seems that the system > really > > only used 2.276 seconds to perform the disk IO, > read the > > directory and count the number of files. > > > > I am not sure whether I missed anything or not. I > really > > cannot understand how the system took about 42 > seconds to > > process the lock on the single directory. > > > > Any further comments? > > > > Thanks again in advance, > > > > Jas > > > > > > --- "Andrew A. Neuschwander" <andrew@xxxxxxxxxxxx> > > wrote: > > > > > I've looked at this problem a bit as well. My > system is a > > 4Gb FC SAN > > > with a bonded GigE DLM dedicated network. > Stat'ing 30,000 > > files in 3 > > > minutes on GFS isn't unreasonable considering > that it must get and > > > release the gfs locks. In this scenario, you are > averaging > > about 6ms > > > per file stat. When we did our tests, all of our > subsystems > > (FC, Net, > > > CPU, Memory, Disk) were near idle. I think the > 6ms is simply the > > > accumulated latency of all the subsystems > involved. There > > is a lot of > > > work happening in that short period of time. > > > > > > -A > > > -- > > > Andrew A. Neuschwander, RHCE > > > Linux Systems/Software Engineer > > > College of Forestry and Conservation > > > The University of Montana > > > http://www.ntsg.umt.edu > > > andrew@xxxxxxxxxxxx - 406.243.6310 > > > > > > > > > On Thu, May 8, 2008 4:29 pm, Bob Peterson wrote: > > > > On Thu, 2008-05-08 at 14:27 -0700, Ja S wrote: > > > >> Hi, All: > > > >> > > > >> I used to post this question before, but have > not received any > > > >> comments yet. Please allow me post > > > it > > > >> again. > > > >> > > > >> I have a subdirectory containing more than > 30,000 small > > files on a > > > >> SAN storage (GFS1+DLM, RAID10). > > > No > > > >> user application knows the existence of the > > subdirectory. In other > > > >> words, the subdirectory is > > > free > > > >> of accessing. > > > >> > > > >> However, it took ages to list the > subdirectory on > > > an > > > >> absolute idle cluster node. See below: > > > >> > > > >> # time ls -la | wc -l > > > >> 31767 > > > >> > > > >> real 3m5.249s > > > >> user 0m0.628s > > > >> sys 0m5.137s > > > >> > > > >> There are about 3 minutes spent on somewhere. > > > Does > > > >> anyone have any clue what the system was > waiting > > > for? > > > >> > > > >> > > > >> Thanks for your time and wish to see your > > > valuable > > > >> comments soon. > > > >> > > > >> Jas > > > > > > > > Hi Jas, > > > > > > > > I believe the answer to your question is in > the > > > FAQ: > > > > > > > > > > > > > > http://sources.redhat.com/cluster/wiki/FAQ/GFS#gfs_slow > > > > > > > > Regards, > > > > > > > > Bob Peterson > > > > Red Hat Clustering & GFS > > > > > > > > > > > > -- > > > > Linux-cluster mailing list > > > > Linux-cluster@xxxxxxxxxx > > > > > > > > > > https://www.redhat.com/mailman/listinfo/linux-cluster > > > > > > > > > > > > > > -- > > > Linux-cluster mailing list > > > Linux-cluster@xxxxxxxxxx > > > > > > https://www.redhat.com/mailman/listinfo/linux-cluster > > > > > > > > > > > > > > ______________________________________________________________ > > ______________________ > > Be a better friend, newshound, and > > know-it-all with Yahoo! 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