I hate top posting, but since you've got two items I want to comment on,
I'll suck it up for now.
Having SSDs alone will give you great performance regardless of
filesystem. BTRFS isn't going to impact I/O any more significantly
than, say, XFS. It does have serious stability/data integrity issues
that XFS doesn't have. There's no reason not to use SSDs for storage of
immediate data and mechanical drives for archival data storage.
As for VMs we run a huge Zimbra cluster in VMs on VPC with large primary
SSD volumes and even larger (and slower) secondary volumes for archived
mail. It's all CentOS 6 and works very well. We process 600 million
emails a month on that virtual cluster. All EXT4 inside LVM.
I can't tell you what to do, but it seems to me you're viewing your
setup from a narrow SSD/BTRFS standpoint. Lots of ways to skin that cat.
On 09/08/2017 08:07 AM, hw wrote:
PS:
What kind of storage solutions do people use for cyrus mail spools?
Apparently
you can not use remote storage, at least not NFS. That even makes it
difficult
to use a VM due to limitations of available disk space.
I´m reluctant to use btrfs, but there doesn´t seem to be any
reasonable alternative.
hw wrote:
Mark Haney wrote:
On 09/07/2017 01:57 PM, hw wrote:
Hi,
is there anything that speaks against putting a cyrus mail spool
onto a
btrfs subvolume?
I might be the lone voice on this, but I refuse to use btrfs for
anything, much less a mail spool. I used it in production on DB and
Web servers and fought corruption issues and scrubs hanging the
system more times than I can count. (This was within the last 24
months.) I was told by certain mailing lists, that btrfs isn't
considered production level. So, I scrapped the lot, went to xfs
and haven't had a problem since.
I'm not sure why you'd want your mail spool on a filesystem and
seems to hate being hammered with reads/writes. Personally, on all
my mail spools, I use XFS or EXT4. OUr servers here handle
600million messages a month without trouble on those filesystems.
Just my $0.02.
Btrfs appears rather useful because the disks are SSDs, because it
allows me to create subvolumes and because it handles SSDs nicely.
Unfortunately, the SSDs are not suited for hardware RAID.
The only alternative I know is xfs or ext4 on mdadm and no subvolumes,
and md RAID has severe performance penalties which I´m not willing to
afford.
Part of the data I plan to store on these SSDs greatly benefits from
the low latency, making things about 20--30 times faster for an
important
application.
So what should I do?
--
Mark Haney
Network Engineer at NeoNova
919-460-3330 option 1
mark.ha...@neonova.net
www.neonova.net
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