Backup technologies

[tim55]

We need to change our tape backup device, since we have run out of room. Based upon the amount we back up now and the growth over the last year, I would say that in 5 years time we will be backing up about 160GB, and we would certainly be looking for a device to have a service life of at least 5 years.

My personal feeling is that we should be looking at the native capacity, rather than the compressed capacity, as we never get anything like what the manufacturers quote.

The problem appears to be not getting a tape drive with the right capacity, but the transfer rate. As an example, we have an external USB2 HP DAT 160, which regardless of the quoted rate, actually takes well over 8 hours to complete a backup and verify on 67GB of data, which is about 8Gb per hour.

Obviously, backing up 160GB at this rate would be a non-starter, as it must all be done within at the very most 8 hours, preferably faster.

Of course, we are not making things any better by using a USB2 interface, although the server it is connected to is SCSI. However, we may replace the server soon and I don't want to be tied to SCSI, whereas USB does seem a convenient interface.

Does anyone have any thoughts on the best technology for the above? Any ideas gratefully appreciated.

 

[jjjon]

Tim55, your transfer rate of your backup probably as more to do with the profile of the data you're backing up. If you're backing up lots 160GB of small files the backup will be slower than if you were backing up 160GB of larger files. Also check if you have AV scanning on Read access, this may cause a performance hit on the transfer rate (although not always practical to do anything about this)

I would suggest, if it's viable, to run a full backup at the weekend and take the 8GB/hr 'hit' and run Incrementals during the week. I'm not sure about the tapes your are currently using, but a conservative estimate on capacity would be half way between native and compressed (I'm open to correction on this!)

Jon

 

[tim55]

Thanks jjjon.

I have done several test runs and even borrowed a couple of backup devices since my post, so I have got a good idea now of what will work.

AV scanning is off on the server anyway and I think the backup rate is simply something to live with, although I take your point about doing full runs at weekends.

I think I am going to get a 200/400GB HP Ultrium tape unit. It gives all the expansion I need and the data rate is at least three times that of the DAT72 unit. It will use the SCSI interface rather than the more flexible USB but what cost sleeping at night!

Tim

 

[cajuntank]

Take into account the machine requirement to "drive" the tape drive you are looking at. If I recall correctly, the minimum processor for a Ultrium drive is a XEON and 1GB of RAM.... this might not be an issue for you unless your using an older server as a dedicated backup server.
Also, with SATA drives being cheap and large as they are, you might could look at backing up to disk as your primary method and then you could archive that off to tape, say like on a Saturday.

 

[tim55]

Thanks cajuntank.

I did get the 200/400GB HP Ultrium tape unit and it works very well. It does 66GB in just over 4 hours (including verifying), which will just about allow my 160GB estimate in 5 years time to be done in a night. It is connected to our main server, which comfortably meets the processor criteria.

Interesting you mention backing up to disk, because we have introduced that as well. The idea is that if a tape backup fails because of a bad tape, then we still have a backup for that day, but more importantly, if data is accidentally deleted or corrupted, then it is much quicker to recover than someone having to go home to collect yesterday's tape. We also have problems with tapes being changed over times like Christmas holidays, when part of the business still works but the offices that include the servers are closed. However, in case of disaster, we need a "yesterday's tape" off site, so just doing a tape backup at the weekend could potentially loose us a whole week of data.

Tim

 

[LeeMason]

I think that disk to disk backup is definately one of the ways forward for the future of backup technology. Especially if this data can be efficiently replication to an offsite locations to provide built-in Disaster Recovery.


Lee Mason
Optimal Projects Ltd

http://www.opl.co.uk

http://www.backupsanywhere.com

 

[wahnula]

I agree with Lee that disk-to-disk backup is the way of the future...and SBS 2008's lack of support for tape drives bears this out. I use (3) laptop drives in cheapo USB 2.0 cases for offsite, and an onboard SATA 1TB drive for local backup. ou can assemble a 180GB laptop drive w/ case for less that $75, and 1TB 3.5" drives are around $100. My goal is to have 5 backups minimum on the onboard drive and swap the USB drives every 3 days for offsite.

This scenario means 2 full backup procedures nightly, so I don't know if you have that kind of time. I use good 'ol SBSBackup (2003), and it has restored twice without a hitch.

Tony

Users helping Users...

 

[cajuntank]

I use Microsoft's DPM2007 product and it does what's called express backups every night and snapshots of changes every 30 minutes. I then archive that off once a week to a tape library. So basically I can go back and restore from any 30 minute interval going back for 2 months off of disk and of course further back if need be from the tape archive. I was a BackupExec guy for the longest, but their product has become so bloated and cluegy that I wanted something cleaner. DPM sure fits the bill and it's nice that if I ever did run into a Exchange,SQL, or Sharepoint restore issue, that I wouldn't have to have two vendors involved pointing the fingers at each other.

 

[ShackDaddy]

I've been using DPM 2007 at some sites and ShadowProtect at others. The thing I wanted to point out is that if you are backing up hundreds of thousands of small files, it would be best to be doing that with some sort of block-level imaging backup, because file-level backup will take forever.

If you can put in a disk to disk to tape rotation system together that you trust, you can then start doing imaging with incrementals and maybe do a full backup once a month, particularly if the backup software you are using will collapse your incrementals into new fulls for long-term storage without having to actually run new fulls. I like how DPM and similar VSS-based tools do that.

Dave Shackelford
ThirdTier.net