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XFS: the filesystem of the future?

XFS: the filesystem of the future?

Posted Feb 2, 2012 16:57 UTC (Thu) by jd (guest, #26381)
In reply to: XFS: the filesystem of the future? by Otus
Parent article: XFS: the filesystem of the future?

Cache would not be a problem if:

(a) it was battery-backed, and
(b) was write-through

Battery-backed doesn't have to mean the whole drive has to remain powered-up, it just has to mean the DRAM gets enough juice to keep refreshing until regular power is restored *if* there is any unwritten content in it. In other words, if everything is flushed to disk then you don't need to keep the drive's RAM powered. If drive manufacturers were *really* clever, then only those blocks of RAM with unflushed content would need to remain powered.

It's hard to get a frame of reference, as most devices with RAM and a modern LIon battery also have a power-hungry CPU and an even hungrier RF system to feed. Here, you only need to keep selective RAM chips powered, no processing is required. I have absolutely no idea what kind of leakage of charge good batteries suffer, but it is probably small. Just keeping DRAM alive doesn't take a vast amount of power. This solution should be adequate to handle even Katrina-length power outages. Beyond that, disk corruption is unlikely to be your major concern.

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