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I wonder what this means for practical system design. Do people currently build assumptions about hard drive failure patterns into their systems, in a way tha
by rtm 20y ago
I wonder what this means for practical system design.
Do people currently build assumptions about hard drive
failure patterns into their systems, in a way that
they should change? I suppose independent failure
(i.e. copying data to two drives is better than storing
it on just one) is the main assumption behind e.g. RAID;
I wonder whether Google has any new insight there.
- jbert 20y agoYou should be able to improve over naive RAID by pairing a relatively-high-probability-of-failure drive with a low prob one. i.e. what you *shouldn't* do is the common practice of putting two new drives in a mirror, since they are both in the infant mortality part of the failure curve. What this data suggests is that you'll get a smaller chance of losing data (via simultaneous failure) if you pair a new drive with an older "proven" one (but not one so old that it is nearing end of life).
- charliehotel 20y agoinfant mortality is practically non-existent for enterprise-class drives and rare for consumer-class drives. there is something to gain by using drives from different manufacturers (or different lots from the same manufacturer) within an array.
- Arrington 18y agoThis is why we can't have nice things.
- Elfan 20y agoCompanies would be interested in saving on cooling costs if its not providing any significant benefit.
- Arrington 18y agoThis is why we can't have nice things.
- charliehotel 20y agoyes, the classic RAID paper assumes that faults are independent. this is not the case. some recent work extends the basic analysis to deal with correlated faults.
- Arrington 18y agoThis is why we can't have nice things.