DL380G5 local logical drive Linux Deivce name changed after connect to MSA500G2

[richeal75]

configuration:
DL380G5 +SA642+MSA500G2
OS: redhat AS 4 u4
problem:
DL380G5 local logical drive Linux Deivce name :/dev/cciss/c0d0

but Deivce name :/dev/cciss/c0d0 changed to :/dev/cciss/c1d0 after connect to MSA500G2

and Linux still can startup .

but customer want to know the root casue.

thanks for your help in advance !

zhangyi

[sandeep_raman · Accepted solution]

Hello zhangyi,

Are you using the Sa642 to connect both the internal and external disks?

If yes,

The Sa642 controller supports two SCSI channels.One port controls the internal SCSI channel, while the other controls the external SCSI channel. When the server boots, external SCSI channel is scanned first. Linux system recognizes the first SCSI drive as sda, the second drive as sdb, and so on. Thus, after an external storage is connected to the external SCSI port, the drive order is changed.

Also scsidev may be handy
http://www.penguin-soft.com/penguin/man/8/scsidev.html

SRH

[richeal75]

Hi SRH,

Customer used P400 for internal SAS disk,
and SA642 for MSA500G2.

so i want to know

1.which setting can change hardware detection order of P400 and SA642.

2. Does linux also follow hardware detection order during linux startup.

thanks !

zhangyi

[Marcel Burggraeve]

Hardware detection is being done by the BIOS before the kernel boots and I doubt you can change that order.
After that linux does some detection as well and assigns addresses in the order of which hardware has been found.
If that order is not correct for you there's a bios= option in lilo.conf to force it to use a different order.

Some more information can be found here :
http://www.tldp.org/HOWTO/LILO.html#toc6