Hello Roch, Friday, May 19, 2006, 3:53:35 PM, you wrote:
RBPE> Robert Milkowski writes: >> Hello Roch, >> >> Monday, May 15, 2006, 3:23:14 PM, you wrote: >> >> RBPE> The question put forth is whether the ZFS 128K blocksize is sufficient >> RBPE> to saturate a regular disk. There is great body of evidence that shows >> RBPE> that the bigger the write sizes and matching large FS clustersize lead >> RBPE> to more throughput. The counter point is that ZFS schedules it's I/O >> RBPE> like nothing else seen before and manages to sature a single disk >> RBPE> using enough concurrent 128K I/O. >> >> Nevertheless I get much more throughput using UFS and writing with >> large block than using ZFS on the same disk. And the difference is >> actually quite big in favor of UFS. >> RBPE> Absolutely. Isn't this issue though ? RBPE> 6415647 Sequential writing is jumping RBPE> We will have to fix this to allow dd to get more throughput. RBPE> I'm pretty sure the fix won't need to increase the RBPE> blocksize though. Maybe - but it also means that until this is addressed it doesn't make any sense to compare ZFS to other filesysystems with sequential writing... The question is how well above problem is understood and when is it going to be corrected? And why in your test cases which are similar to mine you do not see dd to raw device to be actually faster by any important factor? (again, maybe you are using SCSI and I do use FC). -- Best regards, Robert mailto:[EMAIL PROTECTED] http://milek.blogspot.com _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
