zfs discuss - Mar 2009 - Export ZFS via ISCSI to Linux - Is it stable for production use now?

Hello,

I want to setup an opensolaris for centralized storage server, using
ZFS as the underlying FS, on a RAID 10 SATA disks.

I will export the storage blocks using ISCSI to RHEL 5 (less than 10
clients, and I will format the partition as EXT3)

I want to ask...

1. Is this setup suitable for mission critical use now?
2. Can I use LVM with this setup?


Currently we are using NFS as the centralized storage solutions.


Thanks.

howard chen wrote:
> Hello,
> 
> I want to setup an opensolaris for centralized storage server, using
> ZFS as the underlying FS, on a RAID 10 SATA disks.
> 
> I will export the storage blocks using ISCSI to RHEL 5 (less than 10
> clients, and I will format the partition as EXT3)
> 
> I want to ask...
> 
> 1. Is this setup suitable for mission critical use now?
Yes, why wouldn''t it be ?

It is even officially supported as part of the Sun Unified Storage 7000 
series appliances built from OpenSolaris and ZFS technology.
> 2. Can I use LVM with this setup?
Yes you can.

-- 
Darren J Moffat

Hello,

On Wed, Mar 11, 2009 at 10:20 PM, Darren J Moffat
<darrenm at opensolaris.org> wrote:
>>
>> 1. Is this setup suitable for mission critical use now?
>
> Yes, why wouldn''t it be ?
>
Because I just wonder why some other people are using zfs/fuse on Linux, e.g.
http://www.drwetter.org/blog/zfs_under_linux.en.html
http://www.wizy.org/wiki/ZFS_on_FUSE


Also seems hard to find a complete tutorial on accessing ZFS from
Linux using ISCSI. This should be attractive, isn''t?

So I don''t know if it is experimental.

Howard

howard chen wrote:
> Hello,
> 
> On Wed, Mar 11, 2009 at 10:20 PM, Darren J Moffat
> <darrenm at opensolaris.org> wrote:
>>> 1. Is this setup suitable for mission critical use now?
>> Yes, why wouldn''t it be ?
>>
> 
> Because I just wonder why some other people are using zfs/fuse on Linux,
e.g.
> http://www.drwetter.org/blog/zfs_under_linux.en.html
> http://www.wizy.org/wiki/ZFS_on_FUSE
ZFS/fuse on Linux gives you something very different to exporting ZFS 
ZVOLs over iSCSI.  They solve completely different problems.

As for why people play with zfs/fuse on Linux rather than running ZFS on 
OpenSolaris - well because they can, or because their religion means 
they want to use Linux or just to test zfs/fuse.  Same as why people 
play with ZFS on FreeBSD or MacOS X.  Because they can and for what ever 
reasons they have they want to use ZFS and an OS other than OpenSolaris.

None of that implies that sharing ZVOLs over iSCSI isn''t stable.
> Also seems hard to find a complete tutorial on accessing ZFS from
> Linux using ISCSI. This should be attractive, isn''t?
On the OpenSolaris side:

Create your pool:

# zpool create tank <your list of disks and raid config goes here>

Turn on the iSCSI service

# svcadm enable iscsitgtd
[ or if you are on a release with COMSTART make that iscsi/target ]

Create the ZVOL for the iSCSI lun and share it out:

# zfs create -V 10g -o shareiscsi=on tank/lun1

If you want more control over the sharing options see iscsitadm(1M)

That is all that has to be done on the OpenSolaris side to make a 10g 
lun available over iSCSI.  The rest of it is all how Linux sets up its 
iSCSI client side which I don''t know but I know on Solaris it is very 
easy using iscsiadm(1M).

-- 
Darren J Moffat

I blogged this a while ago:

<http://blog.clockworm.com/2007/10/connecting-linux-centos-5-to-solaris.html>

On Wed, Mar 11, 2009 at 1:02 PM, howard chen <howachen at gmail.com>
wrote:
> Hello,
>
> On Wed, Mar 11, 2009 at 10:20 PM, Darren J Moffat
> <darrenm at opensolaris.org> wrote:
>>>
>>> 1. Is this setup suitable for mission critical use now?
>>
>> Yes, why wouldn''t it be ?
>>
>
> Because I just wonder why some other people are using zfs/fuse on Linux,
e.g.
> http://www.drwetter.org/blog/zfs_under_linux.en.html
> http://www.wizy.org/wiki/ZFS_on_FUSE
>
>
> Also seems hard to find a complete tutorial on accessing ZFS from
> Linux using ISCSI. This should be attractive, isn''t?
>
> So I don''t know if it is experimental.
>
> Howard
> _______________________________________________
> zfs-discuss mailing list
> zfs-discuss at opensolaris.org
> http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
>

Hi,

On Thu, Mar 12, 2009 at 1:19 AM, Darren J Moffat
<darrenm at opensolaris.org> wrote:
> That is all that has to be done on the OpenSolaris side to make a 10g lun
> available over iSCSI. ?The rest of it is all how Linux sets up its iSCSI
> client side which I don''t know but I know on Solaris it is very
easy using
> iscsiadm(1M).
>
Thanks for your detail steps.

Bbut I think using this setup, only one client can mount the share
blocks at a time? So there must be a need of clustered file system.
(e.g. gfs)

Just out of curious, what is the clustered file system used in Sun
Unified Storage 7000 series for data sharing ammong clients?

Thanks.

howard chen wrote:
> Hi,
> 
> On Thu, Mar 12, 2009 at 1:19 AM, Darren J Moffat
> <darrenm at opensolaris.org> wrote:
> 
>> That is all that has to be done on the OpenSolaris side to make a 10g
lun
>> available over iSCSI.  The rest of it is all how Linux sets up its
iSCSI
>> client side which I don''t know but I know on Solaris it is
very easy using
>> iscsiadm(1M).
>>
> 
> Thanks for your detail steps.
> 
> Bbut I think using this setup, only one client can mount the share
> blocks at a time? So there must be a need of clustered file system.
> (e.g. gfs)
iSCSI doesn''t enforce that but the filesystem you run on top of the
LUNs
might.  All the Linux side sees is a block device - that is the whole 
point of using iSCSI.  If you don''t want a block device then iSCSI (and
FCoE) are the wrong protocols to be using.
> Just out of curious, what is the clustered file system used in Sun
> Unified Storage 7000 series for data sharing ammong clients?
The S7000 doesn''t use a cluster filesystem it exports ZFS datasets
using
                  one or more of iSCSI, NFS, CIFS, WebDAV, FTP, ie 
network filesystems or filetransfer protocols or a block protocol.

When there is an S7000 cluster configuration the cluster is 
Active/Active with each head controlling one data pool and the services 
for it.  When a cluster head fails the other head takes over the pool 
and the network addresses and starts to provide the services from a 
single head.

This doesn''t require a cluster filesystem

-- 
Darren J Moffat