On Wed, Jan 06, 2010 at 02:20:06PM +0100, Tino Schwarze wrote: > > > > It looks like btape is not happy. > > > > > > > > Error reading block: ERR=block.c:1008 Read zero bytes at 326:0 on > > > > device "Superloader-Drive" (/dev/nst0). > > > > > > > > Are your tapes old (still good)? Did you clean the drive? Latest > > > > Firmware? > > > > The drive requested cleaning just yesterday which I did. I'm not sure > > how old the tape in question really is. I used a dell update utility and > > it updated the drive to v2181 which seems to be the latest for a > > half-height SCSI tape drive. 30MB/s seems a bit low to me - it should be > > able to do 60MB/s per spec. Or is that just theory vs. real world? > > > > > I would add are you using LTO3 tapes or LTO2 tapes? > > > > They are labelled 400GB/800GB - all of the same kind, so they're > > definitely LTO3. The autoloader says: "Drive Idle Gen 3 Data" in it's web > > interface, so yes, I'm sure. > > > > I could check a very new tape tomorrow or try a shiny new one, just to > > be sure. > > Here are the results for a shiny new tape with block size 512k: > > > Wrote blk_block=750000, dev_blk_num=651 VolBytes=391,110,459,392 > > rate=59638.7 KB/s > > 06-Jan 13:50 btape JobId 0: End of Volume "TestVolume1" at 397:1147 on > > device "Superloader-Drive" (/dev/nst0). Write of 524288 bytes got -1. > > 06-Jan 13:50 btape JobId 0: Re-read of last block succeeded. btape: > > btape.c:2345 Last block at: 397:1146 this_dev_block_num=1147 > > btape: btape.c:2379 End of tape 397:0. VolumeCapacity=391,370,506,240. > > Write rate = 59587.5 KB/s > > Done writing 0 records ... > > Wrote state file last_block_num1=1146 last_block_num2=0 > > > > > > 13:50:27 Done filling tape at 397:0. Now beginning re-read of tape ... > > 06-Jan 13:50 btape JobId 0: 3301 Issuing autochanger "loaded? drive 0" > > command. > > 06-Jan 13:50 btape JobId 0: 3302 Autochanger "loaded? drive 0", result is > > Slot 1. > > 06-Jan 13:50 btape JobId 0: 3301 Issuing autochanger "loaded? drive 0" > > command. > > 06-Jan 13:50 btape JobId 0: 3302 Autochanger "loaded? drive 0", result is > > Slot 1. > > 06-Jan 13:50 btape JobId 0: Ready to read from volume "TestVolume1" on > > device "Superloader-Drive" (/dev/nst0). > > Rewinding. > > Reading the first 10000 records from 0:0. > > 10000 records read now at 1:626 > > Reposition from 1:626 to 397:1146 > > Reading block 1146. > > > > The last block on the tape matches. Test succeeded. > > So this looks very promising: 390 GB and I'm also seeing almost 60MB/s. > I will repeat this test using one of the older tapes, then report back. > > Is it possible that the low block size of 64k affects tape capacity? It > looks suspicious to me that all tapes "end" at about the same size...
It feels like the tapes really are worn out. I aborted the new btape test since the throughput was really low: 14:31:54 Begin writing Bacula records to tape ... Wrote blk_block=5000, dev_blk_num=1185 VolBytes=2,620,915,712 rate=24494.5 KB/s Wrote blk_block=10000, dev_blk_num=464 VolBytes=5,242,355,712 rate=24845.3 KB/s Wrote blk_block=15000, dev_blk_num=1650 VolBytes=7,863,795,712 rate=26656.9 KB/s Wrote blk_block=20000, dev_blk_num=929 VolBytes=10,485,235,712 rate=24613.2 KB/s Wrote blk_block=25000, dev_blk_num=208 VolBytes=13,106,675,712 rate=24590.4 KB/s Wrote blk_block=30000, dev_blk_num=1394 VolBytes=15,728,115,712 rate=25532.7 KB/s 14:43:17 Flush block, write EOF All the same config, just an older tape. :-( I'm not sure, how often it's been used because of our rather complicted multi-stage backup scheme (daily/weekly/monthly/yearly pools). Is it possible that the drive simply wastes capacity because of low throughput? What's your experience: How often may a tape be written to? Thanks, Tino. -- "What we nourish flourishes." - "Was wir nähren erblüht." www.lichtkreis-chemnitz.de www.tisc.de ------------------------------------------------------------------------------ This SF.Net email is sponsored by the Verizon Developer Community Take advantage of Verizon's best-in-class app development support A streamlined, 14 day to market process makes app distribution fast and easy Join now and get one step closer to millions of Verizon customers http://p.sf.net/sfu/verizon-dev2dev _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
