On Sat, April 20, 2013 18:22, Pandu Poluan wrote: > On Apr 20, 2013 10:01 PM, "Tanstaafl" <tansta...@libertytrek.org> wrote: >> >> Thanks for the responses so far... >> >> Another question - are there any caveats as to which filesystem to use > for a mail server, for virtualized systems? Ir do the same > issues/questions > apply (ie, does the fact that it is virtualized not change anything)? >> >> If there are none, I'm curious what others prefer. >> >> I've been using reiserfs on my old mail server since it was first set up > (over 8 years ago). I have had no issues with it whatsoever, and even had > one scare with a bad UPS causing the system to experienc an unclean > shutdown - but it came back up, auto fsck'd, and there was no 'apparent' > data loss (this was a very long time ago, so if there had been any serious > problems, I'd have known about it long go). >> >> I've been considering using XFS, but have never used it before. >> >> So, anyway, opinions are welcome... >> >> Thanks again >> >> Charles >> > > Reiterating what others have said, in a virtualized environment, it's how > you build the underlying storage that will have the greatest effect on > performance. > > Just an illustration: in my current employment, we have a very heavily > used > database (SQL Server). To ensure good performance, I dedicated a RAID > array > of 8 drives (15k RPM each), ensure that the space allocation is 'thick' > not > 'thin', and dedicate the whole RAID array to just that one VM. Performance > went through the roof with that one... especially since it was originally > a > physical server running on top of 4 x 7200 RPM drives ;-) > > If you have the budget, you really should invest in a SAN Storage solution > that can provide "tiered storage", in which frequently used blocks will be > 'cached' in SSD, while less frequently used blocks are migrated first to > slower SAS drives, and later on (if 'cold') to even slower SATA drives.
4-tier sounds nicer: 1 TB in high speed RAM for the high-speed layer, with dedicated UPS to ensure this is backed up to disk on shutdown. -- Joost
