Hi, thanks for answering, > How large is your ARC / your main memory? > Probably too small to hold all metadata (1/1000 of the data amount). > => metadata has to be read again and again
Main memory is 8GB. ARC (according to arcstat.pl) usually stays at 5-7GB > A recordsize smaller than 128k increases the problem. recordsize is default, 128k > Its a data volume, perhaps raidz or raidz2 and you are using an older ZPOOL > version? It's raidz, pool version is 22 > Reading is done for the whole raid stripe when you are reading a block. > > => the whole raidz stripe has the attributes of a single disk (see Roch's > blog). > > The number of files is not specified. some 20 files deleted, each about 4GB in size > Updating the dedup table needs random access of the table. dedup was enabled at some point, but I disabled it long ago. Does it still matter? Should I copy all these files again (or zfs send) to un-dedup those blocks? > > ~ 60 reads per second is normal for a sata disk with 7200 RPM. shouldnt ~60 reads per second at about 128k (not counting prefetch) be about 7MB/s, instead of the 144kbps (!) I'm getting? > > so far nothing suprising... > > > Regards, > > Ulrich > > > > ----- Original Message ----- > From: drge...@gmail.com > To: zfs-discuss@opensolaris.org > Sent: Monday, July 19, 2010 5:14:03 PM GMT +01:00 Amsterdam / Berlin / Bern / > Rome / Stockholm / Vienna > Subject: [zfs-discuss] Deleting large amounts of files > > Hello, > I think this is the second time this happens to me. A couple of year ago, I > deleted a big (500G) zvol and then the machine started to hang some 20 > minutes later (out of memory), even rebooting didnt help. But with the great > support from Victor Latushkin, who on a weekend helped me debug the problem > (abort the transaction and restart it again, which required some black magic > and recompiling of ZFS) it worked. > > Now I'm facing a similar problem. I was writing about 20GB (from CIFS) to a > filesystem. While that was going, I deleted some old files, freeing up about > 60GB in the process. After Windows was done deleting those (it was instant), > i tried to delete another file, which I didnt have permision to. So I SSHd to > the machine and removed it manually (pfexec rm file). And thats where > problems started. > > First, I noticed the rm wasnt instant. It was taking long (over 5 minutes). I > tried Ctrl-C, Ctrl-Z, another SSH and kill, nothing worked. After a while it > died with "killed". I did a "zfs list", and noticed the free space wasn't > updated. > > I tried "sync", it also hangs. I try a reboot - it won't, I guess it's > waiting for the sync to finish. So I hard reboot the machine. When it comes > back I can access the ZFS pool again. I go to the directory where I tried to > delete the files with "rm": files are still there (they weren't before the > reboot). > > I try a "sync" again. Same result (hang). "top" shows a decreasing amount of > free memory. zpool iostat 5 shows: > > rpool 69.4G 79.6G 0 0 0 0 > tera 3.12T 513G 63 0 144K 0 > ---------- ----- ----- ----- ----- ----- ----- > rpool 69.4G 79.6G 0 0 0 0 > tera 3.12T 513G 63 0 142K 0 > ---------- ----- ----- ----- ----- ----- ----- > rpool 69.4G 79.6G 0 0 0 0 > tera 3.12T 513G 62 0 142K 0 > ---------- ----- ----- ----- ----- ----- ----- > rpool 69.4G 79.6G 0 0 0 0 > tera 3.12T 513G 64 0 144K 0 > ---------- ----- ----- ----- ----- ----- ----- > rpool 69.4G 79.6G 0 0 0 0 > tera 3.12T 513G 65 0 148K 0 > > Could this be related to the fact that I THINK i enabled deduplication on > this pool a while ago (but then I disabled it due to performance reasons)? > > What should I do? Do I have to wait for these "reads" to finish? Why are they > so slow anyway? > > Thanks, > Hernan > -- > This message posted from opensolaris.org > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss > _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
