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> average about two drive failures a month You must be having a real huge postgres setup with several hundreds of drives to have such high frequency of failure. > As a place to put "one more I didn't expand but that's what I meant. The copy in cloud to be your final resort incase the LAN and the WAN copy both fail. You get an extra copy in a different geographic location for some catastrophic event.> copy" it might make sense, as long as it had strong encryption. > Date: Tue, 22 Jun 2010 09:46:46 -0500 > From: Kevin.Grittner@xxxxxxxxxxxx > To: b_ki@xxxxxxxxxxx; pgsql-admin@xxxxxxxxxxxxxx; qcor@xxxxx > Subject: Re: db recovery after raid5 failure > > Balkrishna Sharma <b_ki@xxxxxxxxxxx> wrote: > > > If the database is not extremely huge, makes you wonder what does > > a RAID actually give us. > > Well, RAID5 gives you a situations where you must have a second > drive fail before recovery for the first failure is complete, versus > being instantly dead on a single-drive failure. RAID6 requires > three drives to fail in close succession (assuming a hot spare which > initiates recovery on failure). RAID10 requires that two paired > drives fail. We have about 100 database servers, and probably > average about two drive failures a month; having any down time from > them is rare because of RAID (and that's with us primarily using > RAID5). > > > A robust near-realtime replication setup (say PITR + cloud) > > may be good enough against once in a few years of disk > > failure.atleast you don't add another point of failure that you > > (your database/OS) can't do anything about. > > You've totally lost me there. "The cloud" still uses similar > techniques, just out of your sight and control. If you assume that > whoever is running it can do it better than you can, that's one > thing; just don't assume it's magic. The machines in my shop are > what I *can* do something about. Management here insists on near- > real-time backup using at least two completely independent > techniques to multiple machines in multiple buildings, with > continuous testing that all backups actually restore. If we were to > float data off into a cloud somewhere, I can guarantee we wouldn't > count on it without an alternative. As a place to put "one more > copy" it might make sense, as long as it had strong encryption. > (Again, you've lost all control over who has what access once you > send it into the cloud.) > > -Kevin > > -- > Sent via pgsql-admin mailing list (pgsql-admin@xxxxxxxxxxxxxx) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-admin The New Busy think 9 to 5 is a cute idea. Combine multiple calendars with Hotmail. Get busy. |
