On Apr 21, 2013 4:51 PM, "J. Roeleveld" <jo...@antarean.org> wrote: > > 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. >
Indeed! But 1 TB is kind of overkill, if you ask me... :-D VMware and XenServer can 'talk' with some Storage controllers, where they conspire in the background to provide 'victim cache' on the virtualization host. Not sure about Hyper-V. I myself had had good experience relying on EMC VNX's internal 8 GB cache; apparently the workload is not high enough to stress the system. Rgds, --
