Re: hot-add unformatted drive to RAID array automagically

[Marc Schiffbauer <marc@schiffbauer.net>]

* Alexandros Papadopoulos schrieb am 02.02.05 um 18:56 Uhr:
> We're about to purchase a new server box that has to be as easy to 
> maintain and as fail-safe as (within reasonable bounds) possible.
> 
> Obviously one of the most sensitive and messy failure components are the 
> hard drives. To defend against random drive failures, I want to have a 
> machine that will do RAID-1 (simple mirroring) with two active drives 
> and one hot-standby drive.
> 
> That's easy to setup with mdadm, but my goal here is to make this system 
> as easily maintainable as possible. I'm assuming that a clueful 
> administrator that will know how to prepare the new disk and then add 
> it to the array will NOT be around, so this is how it has to work:
> 
> When a disk fails, one has to be able to just pull it out of the running 
> box (hot swap). In the meantime, the array will be rebuilding with the 
> hot-standby disk, so in a couple of hours there will be a functional 
> RAID-1 array again, but with no standby disk.
> 
> After buying a new (unformatted) disk, the maintainance person will then 
> just have to plug the new disk in the box, at which point it will be 
> recognized and added (as a hot standby) to the array.
> 
> No partitioning, no typing, no downtime. With what kind of hardware is 
> this possible? I assume SCSI hot-swappable drives, the right case and a 
> SCSI RAID controller will do the job. Can anyone recommend specific 
> controllers that will play nicely with Debian (sarge)?

In the past I have been very happy with ICP-Vortex controllers.
But today you can have it a bit cheaper:

You may use one of those wonderful 3ware IDE-RAID Controllers (No
SW-Raid crap like promise or highpoint...) and plug some IDE-Drives
into it.

IIRC 3ware also provides hotswap cases for IDE-Drives (SATA?)

This will safe you alot of money as the drives are alot cheaper...
-Marc


> 
> We have the functionality described above with a M$ box running on a HP 
> Proliant server with a RAID-5 configuration. If RAID-5 is simpler to 
> implement than RAID-1 + hot-standby, we'll go for that (although the 
> latter minimizes the chance of loosing the filesystem).

RAID-5 is slower than RAID-1

-Marc
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