Hello przemolicc, Tuesday, February 27, 2007, 11:28:59 AM, you wrote:
ppf> On Tue, Feb 27, 2007 at 08:29:04PM +1100, Shawn Walker wrote: >> On 27/02/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: >> >On Thu, Feb 22, 2007 at 12:21:50PM -0700, Jason J. W. Williams wrote: >> >> Hi Przemol, >> >> >> >> I think Casper had a good point bringing up the data integrity >> >> features when using ZFS for RAID. Big companies do a lot of things >> >> "just because that's the certified way" that end up biting them in the >> >> rear. Trusting your SAN arrays is one of them. That all being said, >> >> the need to do migrations is a very valid concern. >> > >> >Jason, >> > >> >I don't claim that SAN/RAID solutions are the best and don't have any >> >mistakes/failures/problems. But if SAN/RAID is so bad why companies >> >using them survive ? >> >> I think he was trying to say that people that believe that those >> solutions are reliable just because they are based on SAN/RAID >> technology and are not aware of the true situation surrounding them. ppf> Is the "true situation" really so bad ? ppf> My feeling was that he was trying to say that there is no SAN/RAID ppf> solution without data integrity problem. Is it really true ? ppf> Does anybody have any paper (*) about percentage of problems in SAN/RAID ppf> because of data integrity ? Is it 5 % ? Or 30 % ? Or maybe 60 % ? ppf> (*) Maybe such paper/report should be a start point for our discussion. See http://sunsolve.sun.com/search/document.do?assetkey=1-26-102815-1 as one example. This is entry level array but still such things happens. I do also observer similar problems with IBM's array (larger). It's just that people are used to fsck from time to time not really knowing why and in many cases they do not realize that their data is not exactly what they expect it to be. However from my experience I must admit the problem is almost only seen with SATA drives. I had a problem with SCSI adapter which was sending some warnings (driver) but still was passing IOs - it turned out data were corrupted. Changing SCSI adapter solved the problem. The point is that thanks to ZFS we caught the problem, replaced bad card, did zpool scrub and everything was in perfect shape. No need to resynchronize data, etc. Another time I had a problem with FC array and lost some data but there's no ZFS on it :((( On all other arrays, jbods, etc. with SCSI and/or FC disks I haven't seen (yet) checksum errors reported by ZFS. -- 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
