[KLUG Members] Re: RAID -- Rsync?

[Bryan J. Smith]

Quoting John Pesce <pescej@sprl.db.erau.edu>:
> We have a 1TB RAID5 array that lost two drives at the same time. 
> <sigh>

Ouch!

> It was on our critical file server. Needless to say panic followed
> and schedules were delayed....
> We bought an identical unit and a different brand of drives just for 
> diveristy. We really wanted to now mirror two RAID5 arrays.
> The RAIDs are Promise Ultratrak SX8000s. Adaptec said we could use one
> of thier SCSI RAID cards to mirror the RAID5s. However, now that
> I'm trying to configure the RAID card for RAID1 it says there are
> no usable drives.
> However, it detects the devices on bootup at the proper size. 
> Adaptec now says I can't do this. I bit late.

[ TheBS, who lives within 5 minutes of and knows several people at the east
Orlando Adaptec RAID support center, bites his tongue. @-]

> I looked at Linux software RAID, but the man pages are littered with 
> words like BACKUP and MANY BUGS.

Well, it depends.

I used the older MD approach, and software RAID-1 worked quite well there for
me.  But I _do_ find that "recovery" in _any_ "software RAID" implementation is
rather confusing.

The newer LVM implementation is supposed to be better.

> So this brings me down to running one RAID as the active drive and 
> mirroring the changes each night to a second identical RAID drive.
> Is there a program for this?

Rsync?  It might actually be a good idea to use a complete system as a mirror,
over a dedicated, point-to-point Gigabit network connection, which rsync would
also enable you to do as well.

> Is there a recommend way to keep two drives in sync?
> I thinking a cron job?

Using a "find|cpio", right?  Not ideal IMHO.

-- 
Bryan J. Smith, E.I.            Contact Info:  http://thebs.org
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