# [Solved] Connecting external SCSI Array to a Gentoo Box

## TJNII

Okay, here is the disclaimer first:  This is for a work machine and I'm (currently) at home.  I did the initial troubleshooting this afternoon and got no love.  However, the box in question is currently running tests which won't be finished till next week.  (Yay faults that won't repeat!)  So, I won't be able to dig into this until sometime next week when I can reboot the box without interrupting work.  During the down time I want to make sure I'm not missing anything.  That said:

I'm trying to connect a HP 2100 SCSI disk array to a older IA64 desktop via a LSI PCI-X SCSI card.  (I'm using old junk so nobody will steal it from me.  If I use good stuff it can and will get repurposed.)  As I'm sure you noticed in the disclaimer, the system was already up when I connected the array.  According to make menuconfig, I need the Fusion MPT drivers for this card which I have compiled in.  The array has 4 36G disks in in, and I set the switch on the back to A.  When I powered on the array I got ... nothing.  One of the drives lit up, but that is it.  Nothing in dmesg.  There is a terminator on the unused port of the unit.

So, when I can, I plan to try a couple things:

*) Rebuild the kernel and reboot the machine to make sure the kernel has the support I think it has

*) Reboot the box with the array attached in case it is only scanned at boot.

*) The disks in it are 15k disks, which *may* not work in the 2100 chassis.  I may try switching to 10k disks.

Is there anything else I should try?  Am I missing something obvious?  Will it only show up at boot, not on hotplug?  Could I have hosed it by hotplugging the SCSI cable in the first place?  This is old SCSI server / high end desktop hardware I'm not very familiar with.  If you're familiar with this array, can you let me know of any pitfalls?Last edited by TJNII on Mon Jul 19, 2010 9:03 pm; edited 2 times in total

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## eccerr0r

Which IA64 machine is it?  HP ZX6000? Older Itanium1 machine?

Some IA64 machines seem to have weird hardware in it, but the Fusion MPT seems fairly common and should work fine as is.  Are the internal disks showing up on the machine?

SCSI has historically worked fine with hotplug or at least nonconventional power up sequences (many people turn on their peripherals after the main machine is on) but this may or may not allow detection - which I'm not familiar with.  SCSI has traditionally not have autodetect of new devices on the chain, you may need to tell the kernel to rescan the SCSI bus.

I haven't tried it but something like this should do it:

echo "- - -" > /sys/class/scsi_host/host0/scan

I have used 10K and 15K disks in my ia64 machine, both seem to work fine.  Not sure about external arrays but it should work fine.  Except if the array was torn apart and you threw random disks into it...then it'd get confused possibly if it had hardware RAID.

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## TJNII

 *eccerr0r wrote:*   

> Which IA64 machine is it?  HP ZX6000? Older Itanium1 machine?

 

It is an older proc, 900(ish)MHz.  As for the exact specs I'll have to take a message and get back to you.

 *Quote:*   

> Some IA64 machines seem to have weird hardware in it, but the Fusion MPT seems fairly common and should work fine as is.  Are the internal disks showing up on the machine?

 

Yes, but they don't count as the motherboard has an IDE controller and it came (I found it) with IDE disks.  The external disks are the first SCSI disks I tried with this box.

 *Quote:*   

> 
> 
> SCSI has historically worked fine with hotplug or at least nonconventional power up sequences (many people turn on their peripherals after the main machine is on) but this may or may not allow detection - which I'm not familiar with.  SCSI has traditionally not have autodetect of new devices on the chain, you may need to tell the kernel to rescan the SCSI bus.
> 
> I haven't tried it but something like this should do it:
> ...

 

Well, that makes me feel better.  That is very close to what I did.  The main machine was on, I connected the cable, and then powered up the disks.  I'll try that rescan command.  (If I had remembered my laptop I'd try it now, oh well.  Not driving back to work.)

 *Quote:*   

> 
> 
> I have used 10K and 15K disks in my ia64 machine, both seem to work fine.  Not sure about external arrays but it should work fine.  Except if the array was torn apart and you threw random disks into it...then it'd get confused possibly if it had hardware RAID.

 

I found some more documentation and the speed shouldn't matter, I was wrong on that.  I did tear it down and put new disks in it, but the 2100 is a JBOD so I wouldn't expect that to matter.

So, I'm thinking I need to get it to rescan the chain either with a reboot or the command you listed.  Let me do that legwork and get back to you.  Thanks for humoring me on this "What could it be" post.

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## krinn

you can lspci -k to see if you have the proper driver running, or dmesg should also produce an output for the scsi card, that at least the driver is load, and also (but depend on driver) the scanning result.

You can even build the module and install it, then modprobe it without a reboot as your computer is running and you aren't sure if the driver is working, i suppose the card isn't yet in use.

if the card is in use already (with internal disks), you should check the number of lines (channels) the card provide, some card share internal/external channel but not all, if not, and your card only have 1 line, it means you'll have to choose using external disks or internal ones but not both.

never heard of disk speed problem with an array. 10k or 15k shouldn't care, it's just impact access time, but the array itself, shouldn't care about it.

you can try rescan as eccerr0r said, but don't expect the card to setup the raid itself, so if your box isn't configure to do the raid, you'll have to reboot to enter the card bios to setup a raid array yourself.

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## eccerr0r

If it's JBOD then it should just scan...

Hmm... IDE... I think that narrows down to one machine, HP ZX2000 Itanium2?  These I think are the only desktops that came in 900MHz flavors, the Itanium1's are 733 or 800MHz.  Unfortunately I don't know how much testing the Gentoo devs did with this weird machine, it's like the only one with IDE.  I do know that my ia64 box's ICH4 IDE controller (used for the CDROM) does not seem to work properly with libata...

but I didn't think it had onboard fusion MPT because of the IDE (offboard PCI-X, though, yes...)

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## TJNII

 *eccerr0r wrote:*   

> If it's JBOD then it should just scan...
> 
> Hmm... IDE... I think that narrows down to one machine, HP ZX2000 Itanium2?  These I think are the only desktops that came in 900MHz flavors, the Itanium1's are 733 or 800MHz.  Unfortunately I don't know how much testing the Gentoo devs did with this weird machine, it's like the only one with IDE.  I do know that my ia64 box's ICH4 IDE controller (used for the CDROM) does not seem to work properly with libata...
> 
> but I didn't think it had onboard fusion MPT because of the IDE (offboard PCI-X, though, yes...)

 

Well, it is currently happy with the IDE drives.  No issues, I've been using it for months as my work Linux box.  Aside from VNC I don't need processing power, just I/O so it works well.

It doesn't have onboard SCSI near as I can tell.  It is a PCI-X expansion card.  Just a controller AFAIK, I'm debating doing software raid or just using the attached drives as dump disks.  Pros/cons for both, I'll decide once I get it up.

 *krinn wrote:*   

> you can lspci -k to see if you have the proper driver running, or dmesg should also produce an output for the scsi card, that at least the driver is load, and also (but depend on driver) the scanning result. 
> 
> You can even build the module and install it, then modprobe it without a reboot as your computer is running and you aren't sure if the driver is working, i suppose the card isn't yet in use.

 

I didn't think to grep dmesg and lspci -k is a usefull tool I (shamefully) didn't know about.  (I knew of lspci, I'm not that sad.)  As for building it as a module, that was my original intention but I had already compiled the drivers in when I built the box.  Planning for future needs, probably.  I'm going to try the rescan command first, but I'm due for an upgrade so a reboot is probably a good idea, anyways.

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## TJNII

The problem turned out to be that, while based off the help I thought I needed the MPT Fusion drivers, I actually needed the sym53c8xx driver.  I had built it as a module, but since I thought it was wrong I never modprobed it.  When I rebooted the box it loaded the module automatically.  Then the disks just worked.

Eccerr0r: It is a HP zx2000.  Good guess.

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