Re: iSCSI

[Chavdar Ivanov <ci4ic4%gmail.com@localhost>]

On 25 February 2010 12:25, Stephen Borrill <netbsd%precedence.co.uk@localhost> 
wrote:
> On Thu, 25 Feb 2010, Chavdar Ivanov wrote:
>>
>> On 25 February 2010 09:06, Chavdar Ivanov <ci4ic4%gmail.com@localhost> wrote:
>>>
>>> On 18 February 2010 19:58, Stephen Borrill 
>>> <netbsd%precedence.co.uk@localhost>
>>> wrote:
>>>>
>>>> On Thu, 18 Feb 2010, Martti Kuparinen wrote:
>>>>>
>>>>> I need to setup iSCSI target and I was wondering how
>>>>> good/stable/complete/fast the iSCSI support is in NetBSD 5.99.x. All
>>>>> comments are welcome, especially if you use it with VMware ESXi 4.0.
>>>>
>>>> In-tree iscsi target is fast and stable, but low on features.
>>>
>>> I've got two machines setup as iSCSI targets; the initiator is Windows
>>> 2008R2. One of them, serving three raw disks, never fails (still on
>>> $ uname -a
>>> NetBSD support9 5.99.24 NetBSD 5.99.24 (GENERIC) #0: Tue Feb  2
>>> 16:51:41 GMT 2010
>>> root@uksup2:/usr/obj/usr-current/i386/sys/arch/i386/compile/GENERIC
>>> i386 )
>>>
>>> The other, with slightly newer kernel (but the same has been happening
>>> for quite some time), serving 7 wedges, to the same initiator,
>>> regularly dumps core when the initiator reboots:
>
> Did you spot the -s option which fixed all manner of core dumps as my number
> of targets grew?

I did, but seeing that when I start it manually that it works, didn't
think that that limit is the problem; I may try it later.

>
>>>> I've used it
>>>> as a backend for a Xen farm. However, adding a LUN requires a restart of
>>>> the
>>>> daemon which causes havoc. I've also found it to not work with a Linux
>>>> initiator (or more specifically XenServer).
>>>>
>>>> That's why I imported net/istgt which is used in FreeNAS and looks, on
>>>> the
>>>> basis of my initial experiments, to be ideal.
>>>
>>> I've started to consider switching to this; is there any documentation
>>> other than the example .conf files available?
>>
>> Strike this off; the .conf files are good enough.
>
> Yes, at first glance it looks madly complex, but taking time out for a quiet
> sit-down and a few minute's reflection clears things up.
>
>> I switched to istgt on that machine with no problems.
>
> I've had it reported that 'our' iscsifs initiator is incompatible with istgt
> (by istgt's author):

I haven't yet used iscsifs, usually is the other way around...

>
> "In my quick review of the code, at least, I found following bugs:
> does not accept CHAP challenge length other than 16 octets. (force exit)
> does not handle NOP-OUT CmdSN and immediate bit. (incorrect request)
> does not handle NOP-IN TransferTag=0xffffffff. (segfault)
> does not handle Underflow bit in iSCSI response. (force exit)
> does not set media size properly. (incorrect mount or segfault)"

istgt also could not size properly the wedges I am using - I had to
explicitly specify their sizes in the conf file.

>
> Fixing iscsifs to work with istgt may well have the happy side effect of
> making it work with other currently incompatible targets (e.g. IBM DS3300
> storage).
>
>
> --
> Stephen
>

I am alos having some weird problem with the initiator - as I said,
W2008R2 server; the target is in the favourites table, upon reboot it
eventually restores the seven LUNs I have created ( a whole few
minutes after the connections to my other NetBSD target and to a
Solaris Nevada targets have been restored ) , but the disks never
become online; when I hover over the disks in the Disk Management
console, I get a message that the disk is kept offline due to
administrator's policy; that I couldn't figure out. I have to manually
online the disks to continue using them (that is with istgt; with the
NetBSD target, I often get some of the seven restored, I have to
reconnect to the rest.

Here you are...


Chavdar Ivanov
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