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Re: RAID SCSI 68 pin

Phillipus Gunawan wrote:

I'am a very newbie in scsi raid devices. I collect
some of old scsi hdd to experiment in Debian.

Before I start my experiment, I would like to ask a
few questions

- Is it possible to have different scsi hdd (e.g. 1
hdd 20g with 10k rpm and 50g with 15k rpm) as raid 5
(where more than 1 hdd become 1 partition)

- Would it be possible in Debian to mount a few
diffrent scsi hdd into one partition?

- Is there any docos can lead my way on how to learn
this things?

- If I re-install the Debian, what preparation should
I make to make sure every hdd will back to where it
belongs (the partition offcourse)

Thank You.

Hi Phillipus,

As far as I have experience with SCSI (raid) devices, I'll try to answer your questions...

- It is not possible to have different sized disks in a raid 5 setup. To be exact, it IS possible, but from every disk the size of the smallest disk will be used. So if your smallest disk is 20GB, your RAID array will be (N-1)*20GB in size, where N is the number of disk in your array. Please also note that you need at least 3 disks for RAID5.

- I don't understand your question exactly. When you have a raid array, you have to create virtual disks on it (in case of hardware raid), These virtual disks, together with the partitions that reside on it, are then spread over the different disks.

If you want to spread a single partition over multiple physical disks, I think you should check out LVM (Logical Volume Manager). This way you can distribute partitions over multiple disks and also easily move/resize them, without using RAID.

- Docs? How many do you want? ;-) Just check the numerous HOWTO's that are available (www.tldp.org) or just Google for it. Hardware RAID is quite transparent to use, the RAID array is seen as a harddrive, be it with another device name. Software raid may be a little less easy to set up, although some distro's support it in their installation proces.

I hope this cleared some things up for you.

Best regards,


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