Hi Jason, > My company did a lot of LVM+XFS vs. SVM+UFS testing in addition to > ZFS. Overall, LVM's overhead is abysmal. We witnessed performance hits > of 50%+. SVM only reduced performance by about 15%. ZFS was similar, > though a tad higher.
Yes, LVM snapshots' overhead is high. But I've seen that as you start increasing the chunksize, they get better (though, with higher space usage). So, you saw performance reductions as much as 15% with ZFS clones/snapshots. I'm curious to know what tests and ZFS config (# of snapshots/clones) you ran on. I ran bonnie++ and din't notice any perceptible drops in the numbers. Though my config had only upto 3 clones and 3 snapshots for each of them. > Also, my understanding is you can't write to a ZFS snapshot...unless > you clone it. Perhaps, someone who knows more than I can clarify. Right. I wanted to check if creating snapshots affected the performance of the origin FS/clone. Thanks, Prashanth > On 1/23/07, Prashanth Radhakrishnan <[EMAIL PROTECTED]> wrote: > > > > > > Is there someway to synchronously mount a ZFS filesystem? > > > > '-o sync' does not appear to be honoured. > > > > > > No there isn't. Why do you think it is necessary? > > > > Specifically, I was trying to compare ZFS snapshots with LVM snapshots on > > Linux. One of the tests does writes to an ext3FS (that's on top of an LVM > > snapshot) mounted synchronously, in order to measure the real > > Copy-on-write overhead. So, I was wondering if I could do the same with > > ZFS. Seems not. > > > > Thanks. > > _______________________________________________ > > 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
