On Friday 11 October 2002 10:00, Mike Simpson wrote: >Folks -- > >I've been using amanda for a couple of years now on Sun hardware >(DLT8000-based L9 tape library, with stctl as the tape changer >controller). It's worked great, but I'm nearing capacity with the >current system and trying to decide whether to expand (another L9 > and a load of DLT-IV and Sun-bought holding disk) or switch to > another hardware platform and tape format. I was hoping folks > could take a look at my suggested new setup, and offer advice, > warnings, horror stories, etc. > >The amanda control host would be a smallish Linux rackmount job > with attached SCSI+RAID disk enclosure -- currently I'm > considering a Dell PowerEdge 1650 (1U, PIII-based) with a Dell > PowerVault 220S (3U, 14 x 36 GB Ultra160 SCSI disks + PERC/3 RAID > controller). Doing a RAID-5 + hot spare across the fourteen > disks would give me 400 "real" GB (1024^3) of holding disk. I'd > use RedHat Linux 7.3 for the OS. Main reason for picking Dell > and RedHat over other PC/Linux options is just that they're the > standard for my group these days. For a tape library controller, > I'm hoping that either the "mtx" or "scsi-changer" drivers will > be able to control the library hardware (see below). > >My standard backup "depth" has been to try to have around two > weeks of "dailies", with a short dumpcycle to get a high > proportion of level zeroes onto the tapes (more for convenience > of restores than anything else). I've also got a separate > "offsite" rotation of all level zeroes, run once a week, with > about four weeks of depth, in case the data center ever burns > down. With my current backups, I wind up having the operators > flip the DLT tapes in the L9 every day, which causes lots of > dropped tapes and more wear and tear on the library. I'd like to > get away from that, and wind up with a library capacity that lets > me keep the daily rotation loaded all the time, with an extra > slot so I can load the offsite tape for the week on Monday > morning and then forget about it until the next Monday. > >After poking around, the AIT3 tape format from Sony feels like a > nice direction in which to move (alternatives being sticking with > DLT, or moving to SDLT or Ultrium). I don't know much about > hardware vendors for AIT3 libraries, but two of my candidates are > the QualStar CLS-4216 (2U, with 1 AIT3 drive and 16 tape slots) > or the Overland LibraryPro (4U-ish, with 1 AIT3 drive and 19 tape > slots). Either of these would let me load two weeks worth of > tapes and a weekly offsite. I'm assuming I'd wind up with two > libraries and two amanda rotations with about 200+ GB of data in > each. I could go with software 2:1 compression to save on > holding disk, or dump to disk uncompressed and then try to get > the mythic 2.6:1 hardware compression advertised for the AIT3 > format. > >Does the above sound reasonable? terrible? Have I missed any >compatibility issues, and does anyone use a setup similar to this > one? > >Thanks for any and all advice, > >-mgs About the only comment I'd make is related to compression, particularly hardware compression thats done in the drive. Shut it off because its useage hides the true tape capacity from amanda and may cause EOT mistakes, and use client best for those parts of it that are compressable. A directory full of rpms and other archives won't compress any more, and may in fact grow some.
Server would be nice, but would be done sequentially taking a longer time, whereas the clients can be paralleled even if they are slower, and of course compressed data uses less bandwidth to move it to the server. Here, I rsync the client an hour ahead of time, so its all local to this disk(singular) and my 'server best' gets me a tape thats about 30% of the raw data size on the avrerage run. On this machine, the runtimes of the compressor seem to about equal the time to write the tape on average, so its tolerable. The drive is a 46 gigger, the tapes are 4gb DDS2's. -- Cheers, Gene AMD K6-III@500mhz 320M Athlon1600XP@1400mhz 512M 99.17% setiathome rank, not too shabby for a WV hillbilly
