Re: [zfs-discuss] Re: SPEC SFS benchmark of NFS/ZFS/B56 - please help to improve it!
Leon Koll writes: > An update: > > Not sure is it related to the fragmentation, but I can say that serious > performance degradation in my NFS/ZFS benchmarks is a result of on-disk ZFS > data layout. > Read operations on directories (NFS3 readdirplus) are abnormally time > consuming . That kills the server. After cold restart of the host the > performans is still on the flour. > My conclusion: it's not CPU, not memory, it's ZFS on-disk structures. > > > This message posted from opensolaris.org > ___ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss As I understand the issue, a readdirplus is 2X slower when data is already cached in the client than when it is not. Given that the on-disk structure does not change between the 2 runs, I can't really place the fault on it. -r ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Re: SPEC SFS benchmark of NFS/ZFS/B56 - please help to improve it!
Hello Leon, Wednesday, February 14, 2007, 10:35:05 AM, you wrote: LK> An update: LK> Not sure is it related to the fragmentation, but I can say that LK> serious performance degradation in my NFS/ZFS benchmarks is a LK> result of on-disk ZFS data layout. LK> Read operations on directories (NFS3 readdirplus) are abnormally LK> time consuming . That kills the server. After cold restart of the LK> host the performans is still on the flour. LK> My conclusion: it's not CPU, not memory, it's ZFS on-disk structures. LK> Before jumping to any conclusions - first try to eliminate nfs and do readdirs locally - I guess that would be quite fast. Then check on a client (dtrace) the time distribution of nfs requests and sends us results. You may also want to fiddle with async clusters on a nfs client to see if it makes any difference. -- Best regards, Robertmailto:[EMAIL PROTECTED] http://milek.blogspot.com ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
[zfs-discuss] Re: SPEC SFS benchmark of NFS/ZFS/B56 - please help to improve it!
An update: Not sure is it related to the fragmentation, but I can say that serious performance degradation in my NFS/ZFS benchmarks is a result of on-disk ZFS data layout. Read operations on directories (NFS3 readdirplus) are abnormally time consuming . That kills the server. After cold restart of the host the performans is still on the flour. My conclusion: it's not CPU, not memory, it's ZFS on-disk structures. This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss