On 10/26/11 5:58 PM, Eric Shubert wrote:
On 10/26/2011 04:51 PM, Casey wrote:
On 10/26/11 3:44 PM, Eric Shubert wrote:
I think that with the size of HDDs these days, LVM is a layer of
complexity that has little to no benefit any more. Since you really
want everything mirrored on raid-1 anyway, I simply start with that,
then add more pairs in raid-10 if needed (as opposed to putting LVM on
top of raid-1).
That's true. The only reason I was even asking was because I put
everything into an LVM when I ran the QMT-ISO install. Thought it might
make it easier adjust partition sizes later if I needed.
It would, but adjusting partition sizes shouldn't really be necessary.
You're right. As long as it is planned out well from the start, you
shouldn't need to fuss with resizing partitions later.
How much storage are you needing?
Well...as much as I can. Eventually my customers are going to want
larger quotas, or their companies will grow, and so will the sizes of
their mailboxes. I believe between the old Solaris server (Pop), and our
newer QMT server (Q2), there is about 180GB of user data. It might be
more, but that number sounds familiar.
A drop in the bucket. ;) I'd just put it all on a couple 2 or 3 TB
drives, and call it done for now. I'd also use commodity sata drives.
Yeah thats one option...SATA drives are definitely more affordable, but
the thing is I have about a dozen 2650's and 2550's, and they are all
hot-swap SCSI. So for now I just need to stick with what I got and make
it work until I budget some money for newer hardware. I think the 146's
are the largest drives you can find for these 2650's, but I could be wrong.
The new server I'm trying to get setup as one of the backend servers is
a Dell PowerEdge 2650, with 5x Hotswappable SCSI bays. I had 73's in
each bay, but just scored a sweet deal on 5x 146GB 15K RPM drives. I was
looking at doing RAID5, to be able to provide more storage. If I went
RAID-10, I lose a use for that 5th drive, and my capacity is reduced.
I've heard great things about RAID-5 as well as RAID-10.
IMO, raid-5 is a PITA. It used to be "fashionable" and still is in
some circles, but I think its time has come and gone. Raid-5 isn't
worth the overhead any more, given the price of large capacity drives.
With the setup you have, I'd use 4 drives in raid-10 with one hot spare.
Personally I've used both. I've had much more hand's on experience with
RAID-5, but even at that I'd say its still been pretty limited. I have a
personal 2650 running in my closet off of a RAID-10. It makes sense to
have a hotspare built-in to the array, but it also just means one more
drive that really isn't being utilized and can't be touched. Eric, in
your experience how does RAID-10 perform in comparison to RAID-5...on a
QMT or a back-end server for an array, how is RAID-10 going to rate for
reads/writes, etc? RAID-10 is also a bit more fault tolerant, isn't it?
You can lose up to 2 drives, as long as they aren't from the same set?
My original thought was to set aside 50GB for the root partition, and
then use the rest for for my mailstore. What would you recommend? I'm
also trying to find away to get this new box setup and then bring Q2 in
as the secondary backend server, without having to reinstall everything.
You don't need anywhere near that for the root partition. 8G is more
than enough. This server handles a light load, but you get the picture:
[shubes@tacs-wan ~]$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 6.7G 2.1G 4.3G 33% /
/dev/sda1 99M 22M 72M 24% /boot
tmpfs 252M 0 252M 0% /dev/shm
tacs-udat:/mnt/stor/udat/mail
55G 5.8G 46G 12%
/net/tacs-udat/mnt/stor/udat/mail
I'd do a raid-1 for boot, raid-1 for /, and the rest on raid-10 for
the mail store. Note, don't be deceived by the above. It's a VM that's
sitting on raid-1. ;)
Ok, I guess you're right 50G is overkill. The way I look at it, is I'd
rather over-allocate and end up with some free space than end up running
out of space on my root partition...but yeah, I see your point. It could
be done with much much less than 50.
So in your RAID-1 for boot, RAID-1 for /, and RAID-10 for everything
else scenario...how many drives are you using? I know RAID-10 is a
4-drive minimum, but are you putting boot and / and individual mirrored
drives, or do they share a common mirror? Also, what are you using as a
RAID controller? Hardware, Linux, fakeraid?
Sorry to bombard you with questions...but they always seem to come in
waves :-P
Thank you thank you for taking the time to help me out!
Casey
Smile Global Technical Support
Submit or check trouble tickets http://billing.smileglobal.com
www.smileglobal.com <http://www.smileglobal.com>
