How do I use a Sony AIT-3 (SDX-700C) drive with my Sun Fire 880 server?

I installed a Sun X6540A (PCI dual-channel single-ended Ultra SCSI HBA) and
it is working fine, but I am getting really low speeds (around 3MB/sec).

I am using the same drive on a Sun Enterprise 450 server using its fast
wide SCSI onboard and I get really good speeds (around 17MB/sec).

What kind of HBA should I use with the 880?

Thanks

In article <opruv8x4uk3k814u@news.fu-berlin.de>,
Vikas Agnihotri <fornewsgroups@vikas.mailshell.com> wrote:
>How do I use a Sony AIT-3 (SDX-700C) drive with my Sun Fire 880 server?
>
>I installed a Sun X6540A (PCI dual-channel single-ended Ultra SCSI HBA) and
>it is working fine, but I am getting really low speeds (around 3MB/sec).
>
>I am using the same drive on a Sun Enterprise 450 server using its fast
>wide SCSI onboard and I get really good speeds (around 17MB/sec).
>
>What kind of HBA should I use with the 880?

I would imagine that you would want the X6758A (Sun PCI Dual Ultra3
SCSI HBA).

You should also compare /kernel/drv/st.conf on both hosts. You would
normally want configuration entries for your AIT-3 drives. Is it possible
the 450 has these and the V880 doesn't?

Tom

On Tue, 02 Sep 2003 19:50:16 -0500, Thomas Insel <tom@tinsel.org> wrote:

>> What kind of HBA should I use with the 880?
>
> I would imagine that you would want the X6758A (Sun PCI Dual Ultra3
> SCSI HBA).

Right, thats what I thought, since the SCSI connector on the back of the
AIT-3 drive has "LVD/SE" written on it! The X6540A is single-ended all
right, but it is not LVD (does that make sense, all these different SCSI
standards are driving me nuts!)

But the fact that it gives good speeds on the onboard SCSI on my E450
(fast wide 20MB/sec SCSI) makes me wonder. Is there something special about
the 880 that I need to do?

i.e. the E450 uses the 'fas' driver, while the 880's X6540A uses the 'glm'
driver. Does this matter?

> You should also compare /kernel/drv/st.conf on both hosts. You would
> normally want configuration entries for your AIT-3 drives. Is it
> possible the 450 has these and the V880 doesn't?

I added the tape-config-list entries to st.conf as per Sony's
recommendation and copied it everywhere. (I didnt reboot, I just
'modunload' the 'st' module and did a 'mt -f /dev/rmt/0 status' to reload
the module with the st.conf entries, is this all right?)

I still think it has to do with the 'glm' driver vs. the 'fas' driver.

Anyone else has experience with this?

Thanks

In article <opruwikvne3k814u@news.fu-berlin.de>,
Vikas Agnihotri <fornewsgroups@vikas.mailshell.com> wrote:
>On Tue, 02 Sep 2003 19:50:16 -0500, Thomas Insel <tom@tinsel.org> wrote:
>> I would imagine that you would want the X6758A (Sun PCI Dual Ultra3
>> SCSI HBA).

>Right, thats what I thought, since the SCSI connector on the back of the
>AIT-3 drive has "LVD/SE" written on it! The X6540A is single-ended all
>right, but it is not LVD (does that make sense, all these different SCSI
>standards are driving me nuts!)

LVD devices can fall back to SE if necessary, with a
performance penalty. Of course, the same thing will
be happening on your 450.

>But the fact that it gives good speeds on the onboard SCSI on my E450
>(fast wide 20MB/sec SCSI) makes me wonder. Is there something special about
>the 880 that I need to do?

>i.e. the E450 uses the 'fas' driver, while the 880's X6540A uses the 'glm'
>driver. Does this matter?

You don't have a choice -- the different chipsets on the
different HBAs require different drivers.

>> You should also compare /kernel/drv/st.conf on both hosts. You would
>> normally want configuration entries for your AIT-3 drives. Is it
>> possible the 450 has these and the V880 doesn't?

>I added the tape-config-list entries to st.conf as per Sony's
>recommendation and copied it everywhere. (I didnt reboot, I just
>'modunload' the 'st' module and did a 'mt -f /dev/rmt/0 status' to reload
>the module with the st.conf entries, is this all right?)

This is good enough, provided the modunload was sucessful.

>I still think it has to do with the 'glm' driver vs. the 'fas' driver.

There are lots of other possible problems -- check cabling
and termination. How are you testing speed? If you're writing
data from a filesystem, you could be seeing the results of
disk differences.

Tom

On Wed, 03 Sep 2003 18:07:31 -0500, Thomas Insel <tinsel@tinsel.org> wrote:

> There are lots of other possible problems -- check cabling
> and termination. How are you testing speed? If you're writing
> data from a filesystem, you could be seeing the results of
> disk differences.

The problem was the terminator. I was using a terminator marked 'LVD/SE'
because thats what the drive says. But, like you say, since my HBA is only
SE (not LVD), everything probably falls back to SE and therefore needs a
plain SCSI terminator.

Anyway, I just replaced my terminator with a plain 68-pin SCSI terminator
and everything is fine. I am getting speeds of around 23MB/sec.

[I am using Joerg Schlling's 'star' utility (the -time switch) to write to
the tape and measure my throughput]

Thanks