Journaling no protection against power drop [LWN.net]

Journaling no protection against power drop

Posted Sep 10, 2009 9:00 UTC (Thu) by hensema (guest, #980)
In reply to: Journaling no protection against power drop by ncm
Parent article: Ext3 and RAID: silent data killers?

> They say they happily stop writing halfway in the middle of a sector, and respond to power drop only by parking the head.

Which is no problem. The CRC for the sector will be incorrect, which will be reported to the host adapter. The host adapter will then reconstruct the data and write back the correct sector.

Of course you do need RAID for this.

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Journaling no protection against power drop

Posted Sep 10, 2009 20:52 UTC (Thu) by Cato (subscriber, #7643) [Link]

And of course RAID has its own issues with RAID 6 really being required with today's large disks to protect against the separate-failure-during-rebuild case.

Without RAID, the operating system will have no idea the sector is corrupt - this is why I like ZFS's block checksumming, as you can get a list of files with corrupt blocks in order to restore from backup.