Hi all, A little story that may interest a number of people... Some background - I run a number of servers using AMI Megaraid controllers for a combination of Raid 5 and mirroring on the various servers. I Just received two 18Gb 7200 RPM hot swap drives ordered a while ago and wanted to see if it was possible to install the drives, partition them, mount them and then use them without a reboot. I would have said it couldn't be done -- but I was wrong. Normally top recognise a new disk you would just unload the scsi driver, reload it and have it re-scan the SCSI bus -- except in this case the root partition on these servers is on the same SCSI controller so the driver can not be unloaded/reloaded. So, in the tradition of 'what the hell, lets see if it works' I installed the two 18Gb drives in the external disk array on one of the servers, and used the megaraid manager from AMI to configure these disks to RAID 1 (mirrored). This worked flawlessly -- but the disk (now known as Logical Drive 3) still isn't known to the Linux kernel and as a result is still not accessible. Normally a reboot would be required at this stage of the game to rescan the SCSI bus. But those clever Kernel programmers are ahead of me already... Simply looking at the existing SCSI config: --- $cat /proc/scsi/scsi Attached devices: Host: scsi0 Channel: 01 Id: 05 Lun: 00 Vendor: HP Model: D5989A Rev: 1.02 Type: Processor ANSI SCSI revision: 02 Host: scsi0 Channel: 03 Id: 00 Lun: 00 Vendor: MegaRAID Model: LD0 RAID1 8677R Rev: C Type: Direct-Access ANSI SCSI revision: 02 Host: scsi0 Channel: 03 Id: 00 Lun: 01 Vendor: MegaRAID Model: LD1 RAID1 8677R Rev: C Type: Direct-Access --- displays all the info the kernel currently has on the known SCSI devices. And through /proc you can instruct the kernel to load another device: (BTW - taken from the SCSI programming HOWTO). $echo "scsi add-single-device 0 3 0 2" > /proc/scsi/scsi Which now shows: --- $cat /proc/scsi/scsi Attached devices: Host: scsi0 Channel: 01 Id: 05 Lun: 00 Vendor: HP Model: D5989A Rev: 1.02 Type: Processor ANSI SCSI revision: 02 Host: scsi0 Channel: 03 Id: 00 Lun: 00 Vendor: MegaRAID Model: LD0 RAID1 8677R Rev: C Type: Direct-Access ANSI SCSI revision: 02 Host: scsi0 Channel: 03 Id: 00 Lun: 01 Vendor: MegaRAID Model: LD1 RAID1 8677R Rev: C Type: Direct-Access ANSI SCSI revision: 02 Host: scsi0 Channel: 03 Id: 00 Lun: 02 Vendor: MegaRAID Model: LD2 RAID1 17365R Rev: C Type: Direct-Access ANSI SCSI revision: 02 --- And the new drive is ready for use WITHOUT A REBOOT!!! I was able to fdisk it, format it, mount it and keep on going. Anyhow... I found this interesting, hope somebody else did. Cheers Jason. --- Jason Ball Electronic Commerce Specialist Corporate Express Australia Ltd Phone: +61 2 9335 0374 Fax: +61 2 9335 0753 Email: [EMAIL PROTECTED] -- SLUG - Sydney Linux Users Group Mailing List - http://www.slug.org.au To unsubscribe send email to [EMAIL PROTECTED] with unsubscribe in the text
