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Rather you always had a back up generator that would let you shut down everything gracefully in the event of a power outage. An uncle that worked in that area
by konjin 6y ago
Rather you always had a back up generator that would let you shut down everything gracefully in the event of a power outage.
An uncle that worked in that area in the 80s/90s had stories about people who still argued these new fangled journaling file systems were pointless.
- KMag 6y agoSGI machines had capacitor banks in the power supplies large enough to power the machine long enough for the kernel interrupt handler to park all of the hard drive write heads. It turns out that the voltage required to keep the write head writing is often less than the voltage required to keep RAM from corrupting. At least for a time, XFS journaling correctness relied on the kernel being able to prevent garbage writes on loss of power. There used to be big caveats to using XFS on non-SGI hardware. Though, I think those caveats were roughly "XFS guarantees aren't much better than ext3/ext4 guarantees on power loss, on non-SGI hardware".