Messages in this thread | | | Subject | Re: ext4 features | From | Trond Myklebust <> | Date | Thu, 06 Jul 2006 22:46:59 -0400 |
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On Thu, 2006-07-06 at 22:42 -0400, Ric Wheeler wrote:
> The point of using checksums (or digital signatures on files) is to be > able to detect when the on disk file has been corrupted - not to look > for updates. With normal disks, even writes that are flagged as correct > will occasionally actually end up corrupt on disk. The rate that you > need to validate the checksums is not at a 4 time a day rate. > > Buying a nice, high array can make this much less of a concern, but > those of us who get stuck using commodity disks should always have a way > of detecting corruption and a backup (either on tape or on another box).
I repeat: you do _not_ need high res ctime/mtime updates in order to figure out whether or not you need to do a daily backup on your file. You do need it in order to figure out if the page you just read in from your NFS server 2 microseconds ago is still valid.
Cheers, Trond
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