Linux XFS

Svavar Örn Eysteinsson | 19 Jun 2012 12:13

Recommendation on XFS Filesystem Creation, Lefthand P4500, iSCSI ?

Hello List.

We recently purchased HP Lefthand 4500 G2 24TB iSCSI SAN Box.
The Box is configured in RAID6. (and yes, we are going to expand that with
another boxes in near future).

I'm running Centos 6.2 with the latest updates on the iSCSI initiator 
machine.
HP DL380 G7 with 24GB in RAM

I need to create a 7TB volume at the start, and grow it in near future.

Are there any recommendation on creating that XFS volume ? Particularly 
regarding
iSCSI and that big ?

This server will act as a fileserver for 50+ machines serving request 
with netatalk
and samba.

Surely I will need to use inode64 option. Right ?

Any recommendation would be much appreciated.

Thanks allot people.
Best regards,

Svavar
Reykjavik - Iceland

(Continue reading)

headers

Mike Grant | 19 Jun 2012 14:17

Re: Recommendation on XFS Filesystem Creation, Lefthand P4500, iSCSI ?

Hi Svavar,

On 06/19/2012 11:13 AM, Svavar Örn Eysteinsson wrote:
> We recently purchased HP Lefthand 4500 G2 24TB iSCSI SAN Box.
> The Box is configured in RAID6. (and yes, we are going to expand that with
> another boxes in near future).
> I need to create a 7TB volume at the start, and grow it in near future.

We have a couple of NAS servers (just direct disk connection, not iSCSI) 
with XFS filesystems up to ~30TB, but didn't do anything special for 
those (just defaults on everything, iirc).

The only problem we had was with filesystems bigger than that, where we 
get kernel crashes due to XFS overflowing the stack.  Apparently this 
may be worse if you NFS-share XFS layered over LVM (more stuff on the 
stack, I guess), but I imagine you'd be fine with 7TB.

Cheers,

Mike.

<br />
<hr />
<p><font face="Arial" size="1">
Plymouth Marine Laboratory<br />
Registered Office: <br />
Prospect Place<br />
The Hoe<br />
Plymouth  PL1 3DH
</font></p>

(Continue reading)

headers

Peter Grandi | 19 Jun 2012 19:00

Re: Recommendation on XFS Filesystem Creation, Lefthand P4500, iSCSI ?

> We recently purchased HP Lefthand 4500 G2 24TB iSCSI SAN Box.
> [ ... ] HP DL380 G7 with 24GB in RAM [ ... ]

> I need to create a 7TB volume at the start, and grow it in
> near future.

Why start small and grow? What's the point? Usually "grow" has
no problems, but any restructuring operation (on RAID or
filetrees) is a dangerous moment. Begging for trouble.

> Are there any recommendation on creating that XFS volume ?

Ideally create multiple small volumes over time and assign
different sets of users to them. For better 'fsck' and safety if
anything.

> Particularly regarding iSCSI and that big ?

Hopefully you won't be creating a single 24TB RAID6 set, but
that kind of (euphemism) strategy seems to be standard.

I would not configure the volumes exported by the iSCSI server
as sparse/thin, but in that case using 'discard' should help.

As an obvious note, but just to be sure, you will be running a
64b OS. But still be careful about stack overflows. You are
using 'netatalk' and Samba which are user-level services, so
those won't impact the kernel stack, but DM/LVM and NFS would.
A pity as the only good use of DM would be to create a snapshot
volume for "frozen" state backups. But it should still work,

(Continue reading)