Need Suggestions for Automated Backup

[Alma J Wetzker]

Chong Yu Meng wrote:
> Hmm... I never thought about the size thing. Didn't factor it in.
> 
> I'm not sure about RAID, though -- I'll have to do the sums to see if I 
> can build in some redundancy. Which would you suggest ? Mirroring or a 
> full RAID-5 array ? I'm thinking now of maybe dumping everything into an 
> external hard drive since it's actually cheaper (and faster) than tape. 
> But I won't be able to keep many "snapshots" of the data, I imagine. 
> Typically, how many days data does a company keep?
> 
> Thanks and Regards,
> pascal chong
  [snip]

When my paycheck (and a LOT of others) depended on things like this, We made 
full backups every weekend, month, quarter and year.  We kept the full backups 
off-site with a company that provided that service.  We did incremental 
backups daily and kept those in a fireproof safe in the data center.  We also 
did full backups before and after inventories for auditing purposes.  I 
imagine how much you keep will depend on your accounting cycle and how much 
you want to spend.

Mirroring with RAID (10) is expensive but fast read and write.  If that is 
what you are thninking, you fracture the mirror, replace a drive and reenable 
the mirror.  Be prepared for a system stall as the drive is copied.  RAID (5) 
is about as fast on reads but the writes are much slower.  It requires fewer 
drives but full backups need to be done on a separate media (another drive, 
tape, CD, etc.)  Great for data warehouse applications or web sites that don't 
collect data on the same drives.

For just backup, I would recomend an external drive.  The criticality of the 
data should drive when you go to RAID.  (How long can the company survive 
without access to the data on the system?  How long to replace the whole 
server?  Can the data be corrupted, or just lost?  That type stuff should 
drive your level of backup.)  FWIW

     -- Alma