Device File Naming Convention

[Harvey Garner]

Currently running OS 10.20 which can only have maximum 128 devices defined(/dev/dsk/c?t?d?). Another System Administrator said with OS 11.0 - total devices jumps to 256 - is this true? I can't find anything to verify it.

[James R. Ferguson]

Harvey:

Check:
http://www.docs.hp.com/dynaweb/hpux11/@Generic__CollectionView

...JRF...

[CHRIS_ANORUO]

HP-UX OS 10.20 supports filesystem/filesize of 128Gbytes/128Gbytes; while HP-UX OS 11.00 can go upto 1Tbytes/1Tbytes.

[Antoanetta Naghiu]

If you don't count hardware limitation, and bearing in mind that a physical volume consists in on device file, both HP-UX 11 and 10.20 can have max. 255. You can add if you wish, tape drives and cdroms...

[Christian Aichmair]

Hi !
I think the maximum number of (supported) Disks depends mainly on the System type, the Interface-Card type and the (marketing depended) max. supported number of disk devices.

I think there may be MUCH MUCH more than 128 disk devices on HP-UX 10.x, because e.g. with wide SCSI there may be - at least theoretically - 15 disk per Interface. Now image a box which allows e.g. 30 SCSI-Interfaces, than you already have 450 SCSI-disks.

With Fibre Channel, there may be up to 128 devices per Interface, and a V-Class for example allows up to 28 Interfaces ....

You can also have up to 7 LUs per Addres, amybe the number of LUs per SCSI/Fibre Channel Address is now even higehr with 11.x.

There are some systems out there that have more than 4000 (!) disks connected to them ( Fibre Channel RAIDs).
Of course, some operating-problems will arise, e.g. ioscan running over an hour (!), some EMS Monitors timing out, ... if you have a lot ( say more than 500-1000) disks.

Theoretically, I think you can have up to
(c)X*(t)Y*(d)Z devices, where Y=255(Interfaces), Y=127(FibreChannel, 15 with SCSI), Z=7(LUs).

Hope it helps,
Christian