Thursday, April 12, 2007, 11:55:49 PM, you wrote:
WSfc> zfs-discuss-bounces@xxxxxxxxxxxxxxx wrote on 04/12/2007 04:47:06 PM:
>> Management here is worried about performance under ZFS because they had
>> a bad experience with Instant Image a number of years ago. When iiamd
>> was used, server performance was reduced to a crawl. Hence they want
>> proof in the form of benchmarking that zfs snapshots will not adversely
>> affect system performance. They suggested creating, snapshotting,
>> copying and generally messing about with some 1 gb files. The system is
>> an E450 running snv_52 with a 36 gb boot drive, 142 Gb data drive and
>> two 9 gb SAN partitions, one on slow disk, one on fast. The 36 gb is
>> formatted ufs, everything else zfs.
>> I time mkfile'ing a 1 gb file on ufs and copying it, then did the same
>> thing on each zfs partition. Then I took snapshots, copied files, more
>> snapshots, keeping timings all the way. I could find no appreciable
>> performance hit.
>> Is this a sufficient, valid test?
WSfc> I believe mkfile is creating the file padded with zeros; and that ZFS has
WSfc> short-curcuts to avoid storing actual data for such empty files. That
WSfc> would lead me to believe that this is an invalid test.
Only if you turn a compression on in ZFS.
Other than that 0s are stored as any other data.
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