Chris Hoogendyk wrote:

Seann Clark wrote:

All,

I am fairly new to the list, not so new to Amanda (I usually troll IRC when I am looking for help half the time) but I want to poll the group for suggestions to aid in what I am looking into as well. I have a system currently that has 3.12TB of data, which I would like to start backing up regularly, and soon will increase that to a larger number as well. I am looking for a good service tape drive that can take care of the physical offloading of backups, and that plays well with Amanda. I have an old SCSI HP SureStore that I can never get to really back up to (Pity it was a nice drive for the time, esp when I was maxed at 700GB) though it can read the tapes, write to the tapes through Amanda, it just dies partially through and freezes up the drive. What I am after though is a backup system that is tape based. I would prefer non SCSI, but I can work around that.

The other alternative I am looking into is getting a large external case and cramming it full of 1TB hard drives and using that as backup, but I would like a tape system that works well. I haven't gotten that portion to work too well in the past, but since it was a first time doing it, I am very sure it was a fatal user error that was preventing it from happening.

It has a huge amount to do with budget.

Being in a budget conscious department, I settled on a Sony LIB-162A5. Ballpark cost around $5k. Less if you get good discounts. It uses AIT5 tapes (400G native), comes with one drive but can take a second, holds 16 tapes. The somewhat lower cost comes from being a carousel mechanism that is less complex than the typical robots. That also means it is more reliable, but less expandable than the popular lines of robotic libraries.

I think most people are going with LTO. I chose AIT because I liked the technology. It isn't as fast as LTO, but it doesn't shoe shine. I hear plenty of horror stories of people who get a really fast LTO drive and find that they aren't getting any throughput. That's actually because the computer they configure to go with it can't maintain the data throughput that the tape needs, so the tape goes into shoe shining, and the throughput drops even further to dismal levels. Of course, if budget is not an issue, and if you understand your hardware configuration well, then you will configure a backup server that has the capacity to pump data to the tape and keep it going. I have no trouble keeping the AIT5 going at its full rated speed.

Why not SCSI? Most of the tape libraries are SCSI (either directly SCSI or via SAS or Fibre Channel). Mine is LVD320 SCSI. I'm not sure what alternative you are thinking of. Whatever you choose, you have to think about throughput. Figure out how much data you are planning to transfer and then calculate optimal times. You won't typically get optimal, but it will put you in the right ballpark. Be sure to account for bits versus bytes in the various transfer technologies. Network stuff is going to be bits, internal bus transfers are typically bytes. So, I run Gigabit network and my AIT5 will do 25MBytes.

Fortunately, Amanda will smooth the demand over your dump cycle. So, if you are trying to do 3.12TB total, and you break that up into many DLE's, then you may only be averaging 500GB a night or even less, depending on your dump cycle. I'm sure you already know that, but it is a significant part of the calculations and a real advantage over other backup software.

Of course, it certainly doesn't hurt to do both vtapes and tapes. I'm a big fan of redundancy, which is why I run a long tape cycle and have dual holding disks.

~Seann