compression and tape backups

We're a small office, 8 users, single server running Server 2003 with
4 physical drive, 2 logical drives via Raid 1. The server is being
backed up to a DAT72 internal tape drive. Backups run nightly via
Backup Exec. I do incrementals three times a week and fulls twice a
week. I have reached the point where full backups require a second
tape so I am wondering about the advantages/disadvantages of enabling
compression on the drives.

Would it buy me some more time before needing to come up with a
different backup solution?

Would users notice any performance loss?

Do the RAID 1 arrays require any consideration?

TIA

BrianG


decc@dec-clt.com

Hello BrianG,

BE is set by default to compress data, so check that first.

Best regards

Meinolf Weber
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> We're a small office, 8 users, single server running Server 2003 with
> 4 physical drive, 2 logical drives via Raid 1. The server is being
> backed up to a DAT72 internal tape drive. Backups run nightly via
> Backup Exec. I do incrementals three times a week and fulls twice a
> week. I have reached the point where full backups require a second
> tape so I am wondering about the advantages/disadvantages of enabling
> compression on the drives.
>
> Would it buy me some more time before needing to come up with a
> different backup solution?
>
> Would users notice any performance loss?
>
> Do the RAID 1 arrays require any consideration?
>
> TIA
>
> BrianG
>

Typically, DAT72 drives employ hardware compression and because this is
on by default, you will not find you can enable software compression
(using both would just slow things down and result in a negligible
improvement - if any - and backup exec, if memory serves, does not even
allow you to do that).

When you reach a point where your backups are larger than the capacity
of your equipment, you need to review your backup methodology. You may
need to replace the drive. Or consider using partial fulls - for
example, if you have two large folders you backup, consider fully
backing up one on Friday and the other on Monday and doing a
differential or incremental the other days. This reduces your fulls to
once per week, but is that really a problem (I don't know your business
- maybe it is - but most businesses do well with one weekly full and
differential (not incremental) backups during the week)?

RAID 1 has no impact on what you do with backups. Just remember (and it
looks like you understand this already, but as a reminder for others)
RAID is NOT backup - it's redundancy.

-Lee

(E-Mail Removed) wrote:
> We're a small office, 8 users, single server running Server 2003 with
> 4 physical drive, 2 logical drives via Raid 1. The server is being
> backed up to a DAT72 internal tape drive. Backups run nightly via
> Backup Exec. I do incrementals three times a week and fulls twice a
> week. I have reached the point where full backups require a second
> tape so I am wondering about the advantages/disadvantages of enabling
> compression on the drives.
>
> Would it buy me some more time before needing to come up with a
> different backup solution?
>
> Would users notice any performance loss?
>
> Do the RAID 1 arrays require any consideration?
>
> TIA
>
> BrianG

Would I gain anything by turning on disk compression (the "Compress
drive to save disk space" option in Drive:|Properties)? It is logical
that doing so would reduce the size of the data on the disk thereby
fitting it all on the tape once again. I know this would be a short
term solution. What I don't know is whether this is a recommended
practice on a server drive and/or whether doing so would result in a
noticeable performance hit.

BrianG

(E-Mail Removed) wrote:
> Would I gain anything by turning on disk compression (the "Compress
> drive to save disk space" option in Drive:|Properties)? It is logical
> that doing so would reduce the size of the data on the disk thereby
> fitting it all on the tape once again. I know this would be a short
> term solution. What I don't know is whether this is a recommended
> practice on a server drive and/or whether doing so would result in a
> noticeable performance hit.
>
> BrianG

More than likely you would not gain any speed, you all but certainly
would not gain any additional tape space, and you likely would slow
things down in general.

In a very simplistic way, look at compression like this:

File:
hhhhhxxxxxxxxyyyyyyjjjkkkkkkk

Compression looks at that and says:
5h8x6y3j7k

Once it's been compressed ONCE by ANYTHING (including Windows) it's
going to be very difficult to find a way to compress it more... and
telling ANYTHING ELSE to look for a way will usually just slow things
down as it tries to find patterns that don't exist anymore. Further,
compressing the files/folders with the Windows compression will do no
good - whenever it's read, it gets uncompressed.

Why not stager your backups?