Craig Sanders <[email protected]> wrote:
>On Mon, Jul 15, 2013 at 03:33:09PM +1000, Tim Connors wrote: [...] > > >> Does anyone use zfs's dedup in practice? Completely useless. > >yes, people do. it's very heavily used on virtualisation servers, where >there are numerous almost-identical copies of the same VM with minor >variations. > >it's also useful on backup servers where you end up with dozens or >hundreds of copies of the same files (esp. if you're backing up entire >systems, including OS) Are you actually talking about retroactive deduplication here, or just COW? IMHO taking a little extra care when copying VM images or taking backups and ensuring use of snapshots and/of --reflink are usually good enough as opposed to going back and hunting for duplicate data. [...] > >> Au contraire. If you use lvresize habitually, one day you're going >to >> accidentally shrink your LV instead of expand it, and the filesystem >below >> it will then start accessing beyond end of device, with predictably >> catastrophic results. Use lvextend prior to resize2fs, and resize2fs >> shrink prior to lvreduce, and you'll be right. > >the risk of typing '-' rather than '+' does not scare me all that much. That of course assumes you're using a relative size. If you're using an absolute size this is far less obvious. That's the other thing: lvextend -L 32G on a 64G LV will do nothing, as would lvreduce -L 64G on a 32G LV. This is useful when ensuring an LV meets minimum size requirements and saves significant (potentially buggy) testing code. > >i tend to check and double-check potentially dangerous command lines >before i hit enter, anyway. > >craig -- Sent from my phone. Please excuse my brevity. Regards, Matthew Cengia _______________________________________________ luv-main mailing list [email protected] http://lists.luv.asn.au/listinfo/luv-main
