[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-users] How (not) to destroy a PostgreSQL db in domU on powerfail
On Dienstag 24 Februar 2009 Javier Guerra Giraldez wrote: > if you don't have highly reliable hardware, with redundant channels > and battery backed caches, etc. stay away from XFS. That's what I have! RAID Controller, battery backed cache, disk write cache=off, UPS. Well, the UPS didn't help as my daughter switched off the server directly. > it's a pity, but XFS is only as reliable as the hardware you give it. > in other words: you can be really sure that a software issue won't > trash your XFS filesystem; but also that a hardware failure > definitely will. > ext3, OTOH, might not have such an impressive record of correctness; > but it's designed with redundancy in mind. almost all vital > structures are either replicated or reconstructable from other hints. > that makes fsck slow but effective, and in most cases, the journal > analysis done when remounting after an unclean shutdown is enough to > put it back on track. > > i sure wish i could use XFS in more circumstances, but the needed > hardware is prohibitive. Here the answer from XFS developers: ************* The difference is just that you actually see the corruption on XFS while it's pretty silent on extN. If your Hardware (or Hypervisor) is not reliable you _will_ lose data. Either silently or with a spectacular blowup if the filesystem actually has consistency checking (which XFS has a lot). ************* IOW: The problem is that XEN doesn't strictly follow write barriers. Is there a way I can make it do that? mfg zmi -- // Michael Monnerie, Ing.BSc ----- http://it-management.at // Tel: 0660 / 415 65 31 .network.your.ideas. // PGP Key: "curl -s http://zmi.at/zmi.asc | gpg --import" // Fingerprint: AC19 F9D5 36ED CD8A EF38 500E CE14 91F7 1C12 09B4 // Keyserver: wwwkeys.eu.pgp.net Key-ID: 1C1209B4 _______________________________________________ Xen-users mailing list Xen-users@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-users
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