Topic: How similar to the Hard drives have to be for SME 7 RAID?

[christian]

Just trying to figure out the specifics of how similar the HDDs have to be in a RAID config.

The comment is they have to be the same size. What happens if they are not? Do you just waste the difference in size?

The case I'm think is I have a RAID1 with two Maxtor 120GB drives. If I add say a few more Winchester 120GB drives, will it work? Technically I believe they are slightly different byte size and the geometry is also likely different. If this mix and match would work it will greatly simplify my options now and for growth later.

-Christian

[dsemuk]

I cannot recall seeing this question answered in the past, the recommendation always seems to be identical model drives in the raid array.

Maybe if you have the disks available and a machine to put them in you can get SME7 installed and see what happens.

Dave

[gordonr]

Just trying to figure out the specifics of how similar the HDDs have to be in a RAID config.

The comment is they have to be the same size. What happens if they are not? Do you just waste the difference in size?

A number of things may happen, depending on the order in which the drives are probed:

- It just works and the smallest size is used, with the extra space wasted
- Some mirrors end up with both halves on the same disk (bad)
- The installer gives a weird and wonderful partitioning error (ugly)

The case I'm think is I have a RAID1 with two Maxtor 120GB drives. If I add say a few more Winchester 120GB drives, will it work? Technically I believe they are slightly different byte size and the geometry is also likely different. If this mix and match would work it will greatly simplify my options now and for growth later.

-Christian

There is no current option to move from RAID1 to any other configuration. If you want RAID5 (with RAID1 boot), you're going to need to backup, install, restore.

You can certainly add the extra disks as more RAID1 mirrors manually, even if the disks are different sizes. But you may have to resize partitions and filesystems if the new disks are smaller than the existing ones. And you will still end up with the same amount of usable space, just with more redundancy.

You can also use the LVM tools to extend the existing volumes onto new disks.

Those exercises are left to the reader (see the Linux RAID HOWTO).

[raem]

>...see the Linux RAID HOWTO

...and for the benefit of those who object to searching or being told to search and would like it done for them, it took me 3 seconds at google.

http://www.tldp.org/HOWTO/Software-RAID-HOWTO.html

[troykd]

>

...and for the benefit of those who object to searching or being told to search and would like it done for them, it took me 3 seconds at google.

http://www.tldp.org/HOWTO/Software-RAID-HOWTO.html

Ray,

Now if you could just help without the attitude, this forum would improve.

[meofcourse]

- It just works and the smallest size is used, with the extra space wasted

Yup I have a 20GB and a 30GB Maxtor on a test server, and it seems to be working quite fine

[raem]

troykd

> Now if you could just help without the attitude...

My "attitude" IS one of helpfullness, and more so for those who seem to complain about searching, I did the search for them.

I didn't see you posting the same search result, but you are quick to jump to criticise an attitude that you seem to feel I have.
I believe I was again demonstrating how quick and easy it is to find a result by searching, in this case google.

As Charlie said the other day, I don't think it's a good idea to criticise people for not doing what others thought they should do.

I suggest you stop criticising and start contributing.