SLES 11 and iSCSI

[Gooberlx2]

So I'm testing out SLES11 in a VM for a server and iSCSI storage array on order.

Rack server (Dell R610), and an iSCSI unit (Dell Equallogic PS6500e 48T).

The rest of our lab workstations are using Opensuse (10.3 and 11.1), so I was looking at SLES11 to stay within that ecosystem while using the latest version.

Anyway, what I've found is that filesystems via iSCSI won't mount during boot:
- during boot portion of startup, there's /etc/init.d/boot.localfs which mounts and fscks all filesystems identified in /etc/fstab. Unmounted filesystems will fail the boot and require me to log in to a pseudo-rescue mode.
- as a result any iSCSI filesystems will fail the boot because network and open-iscsi aren't initialized until the runlevel 3 scripts.
- adding _netdev does nothing and it seems "hotplug" doesn't work either (I guess it was a feature in previous versions, as all the guides I've read mention it, but must no longer be available).

So I've commented out the test iSCSI filesystem (target created in an Ubuntu Server VM) from fstab and created a "luntab" script in /etc/ which indivdually runs a mount command for each LUN. Then I modified /etc/init.d/open-iscsi to run luntab after logging in to the iSCSI targets.

It works, but it's dirty. Anyone else have experience with SLES11 and iSCSI or ideas about making this a little more "clean".

I will also be trying out RHEL and SLES10 SP2, but the ISOs are still downloading.

edit:
Okay, one thing I did to clean it up a bit and stay within the suse/yast services ecosystem was to move luntab to /etc/init.d, fill out service description and dependency info and then run chkconfig --add luntab

Still...it's just the kind of thing you'd think would work properly out of the box with an established distro like SLES.

 

[M00T]

If suse has a netfs service like RHEL, then add the "_netdev" option to your iscsi mounts in /etc/fstab. Aftwards, "chkconfig netfs on".

 

[Jamie M]

Have you consider using iSCSI Target for Windows?
please answer me when you can.

 

[Gooberlx2]

Originally posted by: Jamie M
Have you consider using iSCSI Target for Windows?
please answer me when you can.

I've played around with the iSCSI iniator in Windows in the past with a demo equallogic unit. It works fine. However, we're using, and sticking to Linux for various other reasons.

M00T, I did look around, but I don't think netfs is part of SLES. One mailing list post I read somewhere seemed to indicate that it may been part of it at one time, but no longer is.

 

[Scarpozzi]

I always found that SLES iSCSI worked best using the initiator from the GUI to configure it. Once the configuration was saved, it started after the system booted without an issue...but I wasn't using it as a boot partition.

I'm assuming you're just trying to connect to a pre-existing share on the Equalogic via iSCSI... Is that the case or are you setting up a target for others to connect to? If you have ESX server, I'd probably let VMware do the iSCSI connection and share the iSCSI volume to the Virtual Machine as a virtual disk. Just pretend you have an iSCSI or TOE card to help your server and think of it that way.

iSCSI doesn't like to be 'shared' with other systems and needs about 600Meg to keep disk lag to a minimum. Also consider running jumbo-frames on your switch port to maximize performance.

 

[Gooberlx2]

Originally posted by: Scarpozzi
I always found that SLES iSCSI worked best using the initiator from the GUI to configure it. Once the configuration was saved, it started after the system booted without an issue...but I wasn't using it as a boot partition.

I'm assuming you're just trying to connect to a pre-existing share on the Equalogic via iSCSI... Is that the case or are you setting up a target for others to connect to? If you have ESX server, I'd probably let VMware do the iSCSI connection and share the iSCSI volume to the Virtual Machine as a virtual disk. Just pretend you have an iSCSI or TOE card to help your server and think of it that way.

iSCSI doesn't like to be 'shared' with other systems and needs about 600Meg to keep disk lag to a minimum. Also consider running jumbo-frames on your switch port to maximize performance.

Right now I was just testing things in a VM. We haven't yet received the equipment. I wasn't planning on actually running SLES in a VM when things arrive....though now I'm going to ponder the idea (gee, thanks. ).

I posted this same issue on the Novell forums, and it seems I'm not the only one. I did use the GUI initiator to set things up, but it seems some things are simply missing, or out of order during the bootup sequence to properly mount and iSCSI filesystem. It's not the boot or root filesystem, just gets mounted to /data.

The crux of it is that network and iSCSI aren't initialized during the boot.xxx scripts. But boot.localfs tries to fsck all filesystems defined in fstab. adding a "hotplug" option in the fstab entry used to alleviate the problem in older SLES versions (it seems), but no longer works in recent versions.

*shrug* So I made my own workaround. I guess I could have ordered an iSCSI HBA on the system, I didn't realize I might need one, and apparently neither did the Dell people who had been in talks with us for quite some time....c'est la vie.

The R610 will access the iSCSI, and will provide NFS, SMB, FTP and web file services. It will also provide some webpages and database functions. The iSCSI won't be shared by multiple machines.

Our server room has a rather beefy backbone and jumbo frame support, and I'll be teaming gigabit NICs, so adequate communication between the two won't be a problem.