[plug] Good RAID Howto

[Kai Jones]

Running "dmesg | grep sd" gives the following:

Attached scsi disk sda at scsi0, channel 1, id 0, lun 0
SCSI device sda: 71127040 512-byte hdwr sectors (36417 MB)
  sda: sda1 sda2 < sda5 sda6 sda7 >

I'm guessing this means sda, sda1 and sda2 are the active RAID1 and 
sda5, 6 and 7 are spares because it doesn't yet know the 3 x 73 gig 
disks are plugged in and waiting ?

Cheers
Kai

Kai wrote:
> Hi Shannon,
> 
> Thanks for the info, I'm pretty sure my work email addy is subscribed to 
> PLUG, I sent the original email from my work addy but I'll have to check 
> that since I didn't see any replies to this post at that addy.
> 
> I'm pretty sure I've seen the SCSI hardware info during start-up so the 
> next chance I get to power down the file server and configure the SCSI 
> I'll do it, I'll check out dmesg tomorrow when I get to work.
> 
> Cheers
> Kai
> 
> Shannon Carver wrote:
> 
>> Hi,
>> I'd almost garuntee with an HP NetServer, you'd have a professional
>> hardware RAID controller.  The way to check for that is when the machine
>> boots up, the PC will POST, before it boots the operating system, it'll
>> usually prompt you momentarily for SCSI and or RAID setup panels
>> (Usually with a key combination to enter them, one of the FX keys, or
>> Ctrl+H, although can be anything really).
>>
>> I've got a couple of servers here at work with Compaq Smart Array2
>> cards.  When you enter the setup for the cards, you get a BIOS like
>> screen asking you to create/change/remove active array's.  You can setup
>> your raid array here.
>>
>> The catch with using the raid controllers, is linux will pick the drives
>> up as a different device, for instance, our Compaq cards create devices
>> such as:
>> /dev/c0dp1-x where c0 is the first array, and p1 is the partition on
>> that array.
>>
>> Of course, if the scsi drives are hanging off a plain scsi adapter, you
>> should see them detected on bootup, or by reading /var/log/dmesg and
>> looking for: Dmesg | grep sd
>>
>> Which will usually list all scsi devices found at bootup.
>>
>> Hope this helps
>>
>> Regards
>>
>> Shannon
>>
>> -----Original Message-----
>> From: plug-bounces at plug.org.au [mailto:plug-bounces at plug.org.au] On
>> Behalf Of Kai Jones
>> Sent: Monday, 12 September 2005 10:14 AM
>> To: PLUG
>> Subject: [plug] Good RAID Howto
>>
>> Hi guys and girls,
>>
>> I know the principle of RAID and how it works but I've never had to 
>> configure it before.
>>
>> My current situation is I have an HP Netserver 2000 U3 running Red Hat 
>> with 2.4.2-2 kernel as a file server, currently using 3 x 36 Gig 
>> SCSI's on RAID 1.
>>
>> I have three new 73gig SCSI disks which I want to configure so I can 
>> copy the data from the existing 36 Gig RAID 1 and move those disks to 
>> another machine (or use on a different mount point). The SCSI's are 
>> hot swappable and I'm googing for Linux RAID Howto so I can figure out 
>> what device (eg /dev/sd##) the drives are available at, then configure 
>> the 3 x 73 Gig drives as RAID 1, sync them, mount them and copy the 
>> data across, test it and then move the old 36 gig disks to another 
>> server.
>>
>> I'm currently reading 
>> http://www.tldp.org/HOWTO/Software-RAID-HOWTO-5.html but if anyone has 
>> any suggestions to a HOWTO that may be better/easier please let me know
>>
>> Thanks
>> Kai