Tape drive.

[jazzdrive 0]

We are looking at getting a server with a RAID 1 config. with 73 GB drives. Would a 36/72 Tape drive suffice, or should we go with the 80/160. I'm asking because I'm not really sure what the disadvantages are to compressing the data before backup. The 36/72 is about half the cost of the 80/160.

 

Any help would be appreciated. Thanks.

[ViolentGreen 0]

I can't suggest what to get. I don't know your situation but generally the man downside to compressing before backup is the time it takes to compress. It will take a long ass time to compress 73 GB of data.

[Wicked101 0]

That is correct, it will take very long to compress, but then again, that is why the main backup runs on weekends and the incrimentals everyday.

[AndyFair 0]

The second figure used when quoting capacities on tape drives are assuming that all files stored on the tape can be compressed to the same level (i.e. 50% reduction in size, meaning you can store twice as much data) - but this assumption rarely stands up to daily use - if you're backing up files that are already compressed, you won't get anywhere near this level of compression. With 73Gb of disk space to back up, I don't think this will fit on a 36/72 tape.

 

Also with tape compression, the act of compressing the data is undertaken by the tape drive itself - or the backup software, now I come to think of it, I'm unsure which! - but either way, there shouldn't be any need to compress the data before backing up.

 

The other thing to bear in mind is future system growth - OK, you have 73Gb now, but is that going to stay at 73Gb for the forseeable future? Have you done any long-term capacity planning?

 

Personally, I would go for the 80/160 now, because it will allow room for growth, and avoid having to buy another tape drive a couple of years down the line...

 

Rgds

AndyF

[Sampson 0]

Get the larger drive. Most backup software for tape drives come with compression technology built in. However, compression is variable. Most graphic files are so compressed that they cannot be further comptessed. The larger drive will accomodate the borderline compressed data to be stored.

In addition, since you are going with a raid system, I would suggest using Raid 5. It takes three disks to run Raid 5 but the advantage is that if one of the disks go down, the system will continue to run and after replacing the failed drive, the other two disks will restripe it. I know this seems like a "belt and suspenders" scenario, but if your data is that important, you'd be better served going Raid 5.

[jazzdrive 0]

Thanks for all your replies.

 

I guess I am now convinced that we need a RAID 5. So if we go with 73 GB drives, that would give us 146 GB total storage right?

 

So what size tape drive would you recommend then? It seems I have the choices of not near enough, or overkill.

 

Thanks again.