[CentOS] Multiple LUN support

[Robert Heller]

At Wed, 05 Jan 2011 17:53:16 +0100 CentOS mailing list <centos at centos.org> wrote:

> 
> I have Centos 5.2 and am trying to set up my first tape loader, a 
> Quantum SuperLoader 3. My "cat /proc/scsi/scsi" outputs the following:
> 
> Attached devices:
> Host: scsi0 Channel: 00 Id: 00 Lun: 00
>    Vendor: transtec Model: PV610F16R1C      Rev: 373I
>    Type:   Direct-Access                    ANSI SCSI revision: 05
> Host: scsi1 Channel: 00 Id: 01 Lun: 00
>    Vendor: HP       Model: Ultrium 3-SCSI   Rev: D22D
>    Type:   Sequential-Access                ANSI SCSI revision: 03
> Host: scsi1 Channel: 00 Id: 05 Lun: 00
>    Vendor: HP       Model: Ultrium 4-SCSI   Rev: B54Z
>    Type:   Sequential-Access                ANSI SCSI revision: 05
> 
> 
> It is my understanding that there should be TWO devices for the loader, 
> one for the tape drive and one for itself. From reading around, it seems 
> that it's lacking Multiple LUM support. My question is, are more recent 
> versions of CentOS enabling that by default? Either compiling kernel 
> modules or doing a full upgrade of the system are "big" jobs in my case, 
> but I'd prefer the upgrade if 5.5 works out of the box. Or do I really 
> need to recompile kernel, enable max_lums in modprobe.conf, etc?

The current CentOS 5 kernel (CentOS 5.5: 2.6.18-194.26.1.el5) has
multiple LUN support enabled (this is the stock kernel):

sauron.deepsoft.com% grep LUN /boot/config-2.6.18-194.26.1.el5
CONFIG_PREEMPT_VOLUNTARY=y
# Some SCSI devices (e.g. CD jukebox) support multiple LUNs
CONFIG_SCSI_MULTI_LUN=y

Upgrading to 5.5 is probably a good idea anyway.

> 
> Thank you
> 
> Abe
> 
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-- 
Robert Heller             -- 978-544-6933 / heller at deepsoft.com
Deepwoods Software        -- http://www.deepsoft.com/
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