IHAC who would like to understand following: We''ve upgraded a box to sol10-u4 and created a ZFS pool. We notice that running "zfs iostat 1" or "iostat -xnz 1", the data gets written to disk every 5 seconds, even though the data is being copied to the filesystem continuously. This behavior is different than UFS as UFS continuously writes. So, what''s with the 5 second pause? Any clarification will be appreciated. Thank you Ajay -------------- next part -------------- A non-text attachment was scrubbed... Name: ajay_k.vcf Type: text/x-vcard Size: 266 bytes Desc: not available URL: <http://mail.opensolaris.org/pipermail/zfs-discuss/attachments/20071128/e144bf66/attachment.vcf>
Ajay Kumar wrote:> IHAC who would like to understand following: > > We''ve upgraded a box to sol10-u4 and created a ZFS pool. We notice that > running "zfs iostat 1" or "iostat -xnz 1", the data gets written to disk > every 5 seconds, even though the data is being copied to the filesystem > continuously. > > This behavior is different than UFS as UFS continuously writes. So, > what''s with the 5 second pause?ZFS creates transactions for systems calls that modify the pool. For efficiency it gathers together individual transactions into transaction groups (txgs) which are committed every 5 seconds. If you are seeing some constant background write activity then that is probably due to synchronous writes which require data be stable on return from the system call. These are written on demand to an intent log.> > Any clarification will be appreciated. > > Thank you > Ajay > > _______________________________________________ > zfs-discuss mailing list > zfs-discuss at opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss