[KLUG Members] RAID

[John Pesce]

We have a 1TB RAID5 array that lost two drives at the same time. 
<sigh>
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.

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

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