Amanda backup strategy thoughts, full and incremental backups to tape once a week.
Hello All, I would like to ask a general Amanda backup 'strategy' question here, given by backup 'goals' below. I have a configured and working Amanda set-up but I want to try and fit a backup policy that I believe is best suited to our site around Amanda. I have an 8-tape (DLT 35/70gb each) auto changer library linked to Amanda via mtx, this works well. I want to do a full backup of various file systems on a remote host once a week and then, ideally, incremental backups once a day to that same tape. At the end of a week's backup, the tape should switch. One week's backup is far less than a single tape's capacity. I would like to be able to hold 8 weeks worth of backups on tape, that is one tape a week and then reuse the oldest tape. I'm not sure this is possible with Amanda.. as I believe I can't append the daily incremental backups onto the same tape as the full backups. Is it the case that if I want to run Amanda every day that I would also have to use a tape every day, thus meaning the tapes in the library are all used after a week. I'm fixed in the number of tapes I can use and can't add/replace them, so they would get reused after a week and wouldn't provide much of a 'backup horizon'. If this isn't possible does anyone have some suggestions? I was thinking I could do the incremental backups to a hard disk area on the tape server each night and then run Amanda once a week to archive the full backups plus the HDD incremental ones. Many thanks in advance for everyone's thoughts. William.
Re: Amanda backup strategy thoughts, full and incremental backups to tape once a week.
On Tue, Apr 06, 2004 at 12:12:05PM +0100, William Hargrove wrote: Hello All, I would like to ask a general Amanda backup 'strategy' question here, given by backup 'goals' below. I have a configured and working Amanda set-up but I want to try and fit a backup policy that I believe is best suited to our site around Amanda. I have an 8-tape (DLT 35/70gb each) auto changer library linked to Amanda via mtx, this works well. I want to do a full backup of various file systems on a remote host once a week and then, ideally, incremental backups once a day to that same tape. At the end of a week's backup, the tape should switch. One week's backup is far less than a single tape's capacity. I would like to be able to hold 8 weeks worth of backups on tape, that is one tape a week and then reuse the oldest tape. I'm not sure this is possible with Amanda.. as I believe I can't append the daily incremental backups onto the same tape as the full backups. Is it the case that if I want to run Amanda every day that I would also have to use a tape every day, thus meaning the tapes in the library are all used after a week. I'm fixed in the number of tapes I can use and can't add/replace them, so they would get reused after a week and wouldn't provide much of a 'backup horizon'. If this isn't possible does anyone have some suggestions? I was thinking I could do the incremental backups to a hard disk area on the tape server each night and then run Amanda once a week to archive the full backups plus the HDD incremental ones. Where is that Top Ten Questions document when you need it? Amanda will not reuse a tape for a new run of amdump, fulls or incrementals, until it cycles through tapecycle number of tapes. So you are correct, amanda will NOT append a second amdump to a tape. Amanda only overwrites tapes! However, an amflush can overwrite a tape with multiple dumps from the holding disk. Thus collect as many amdumps as you want with the tape offline. Then amflush when you want to tape them. -- Jon H. LaBadie [EMAIL PROTECTED] JG Computing 4455 Province Line Road(609) 252-0159 Princeton, NJ 08540-4322 (609) 683-7220 (fax)
Re: Amanda backup strategy thoughts, full and incremental backups to tape once a week.
Here's a strategy that I implemented about a month ago that is working pretty well so far: 1. run amdump every night to large RAID w/o tape, mix of full and incr 2. run script to separate images to amanda-incr and amanda-full 3. when amanda-full exceeds size of tape, run amflush 4. when RAID approaches capacity, flush some incrs to tape Since it's a RAID, there is less chance it will go to crap than a regular disk partition, but it is still possible. And if it does, I still have the full dumps on tape to fall back on. To give you some gauge of capacities, I'm backing up about 300 GB of disks, have ~600 GB RAID5 (on a Snap 4500) and am using 100/200 GB LTO (Ultrium-1) tapes. So far, it's mostly web servers, but I haven't moved everything to the new backup cycle yet. I have flushed 2 tapes worth of full dumps, and accumulated about 167 GB of incrementals that are still on the RAID. The goal and idea is that 90% of the time, I will only need to load one tape to do a restore, and the rest will come out of holding files. Even better, there is a good chance that the tape that I need will be the last one that I flushed, so I won't have to change the tape. /snap/amanda-hd is the directory that amanda.conf looks for, which is actually a symbolic link to /snap/amanda-full. Therefore, I just move the incremental dumps from amanda-full to amanda-incr, both actually on the same filesystem (a simple directory rename in the filesystem inode table). If I need to flush incrementals, I just change the link amanda-hd - amanda-incr and run the flush (this could be done more elegantly with a patch, but this is so easy, so why bother?) In the cron job, I make sure amanda-hd - amanda-full before amdump runs. I'm using NFSv3 to XFS filesystem through a dedicated 100baseTX FD connection, so I'm using a chunksize of ~600 GB, and that makes the rename script very simple since I don't have to worry about any backup getting split into chunks. AFAIK NFSv3 and XFS both support 64-bit addressing, so I shouldn't run into any filesize limits. --jonathan
Re: Amanda backup strategy thoughts, full and incremental backups to tape once a week.
In a message dated: Tue, 06 Apr 2004 12:12:05 BST William Hargrove said: I was thinking I could do the incremental backups to a hard disk area on the tape server each night and then run Amanda once a week to archive the full backups plus the HDD incremental ones. I did this once, way back when all I had was a single DLT drive and no autoloader. I would just leave the drive empty all week, and on Friday mornings I would pop that week's tape in then amflush everything to tape. When that was done, I would place the weekend tape in the drive and the full dumps on Saturday night would go direct to tape, or, if I forgot, end up on the holding disk for amflushing Monday morning. This worked quite well IMO for the small environment I had at the time. HTH, -- Seeya, Paul GPG Key fingerprint = 1660 FECC 5D21 D286 F853 E808 BB07 9239 53F1 28EE If you're not having fun, you're not doing it right!
