I just moved my main amanda server to use software compression instead of hardware compression - got tired of banging my head on EOT. The Dump Time went through the roof, but it still finished within my expected backup window. I'm impressed with the way amanda continues to perform for me - kudos to the developers. Makes the $6k we spent on Veritas look reeeeally bad!
I'm slightly baffled at the Tape Time though - it seems to have gone down. I expected it to remain about the same, half the data at half the tape write speed. I'm posting my numbers & changes - comments? Comparison between hardware compression & software compression Amanda server = RH7.1, PIII 550 Mhz, 256M mem, 80G IDE holding disk Tape Drive = AIT-2 scsi Typical results with large backup run using hardware compression: tape length = 70000 M netusage 10000 Kbps maxdumps = 2 Estimate Time (hrs:min) 1:12 Run Time (hrs:min) 9:18 Dump Time (hrs:min) 10:12 7:49 2:23 Output Size (meg) 69757.9 57995.6 11762.3 Original Size (meg) 69757.9 57995.6 11762.3 Avg Compressed Size (%) -- -- -- (level:#disks ...) Filesystems Dumped 93 19 74 (1:74) Avg Dump Rate (k/s) 1944.6 2110.7 1400.9 Tape Time (hrs:min) 3:02 2:16 0:46 Tape Size (meg) 69757.9 57995.6 11762.3 Tape Used (%) 100.0 82.9 17.1 (level:#disks ...) Filesystems Taped 93 19 74 (1:74) Avg Tp Write Rate (k/s) 6541.9 7264.8 4388.6 One of the first runs using software compression: compression = server fast tape length = 48500 M netusage = 10000 Kbps maxdumps = 2 comprate 0.70 , 0.70 Estimate Time (hrs:min) 1:10 Run Time (hrs:min) 9:54 Dump Time (hrs:min) 39:23 31:53 7:30 Output Size (meg) 27744.5 23489.8 4254.7 Original Size (meg) 56949.0 45437.6 11511.4 Avg Compressed Size (%) 48.7 51.7 37.0 (level:#disks ...) Filesystems Dumped 91 27 64 (1:64) Avg Dump Rate (k/s) 200.4 209.6 161.5 Tape Time (hrs:min) 1:25 1:08 0:17 Tape Size (meg) 27744.6 23489.8 4254.8 Tape Used (%) 57.8 48.6 9.2 (level:#disks ...) Filesystems Taped 91 27 64 (1:64) Avg Tp Write Rate (k/s) 5560.0 5919.3 4164.3 After a couple weeks, same as above with these changes: netusage = 40000 Kbps maxdumps = 3 holding disk = 140G reserve = 50 Estimate Time (hrs:min) 1:17 Run Time (hrs:min) 11:29 Dump Time (hrs:min) 27:46 21:57 5:48 Output Size (meg) 42104.5 37389.2 4715.2 Original Size (meg) 71673.5 59705.8 11967.7 Avg Compressed Size (%) 58.7 62.6 39.4 (level:#disks ...) Filesystems Dumped 91 15 76 (1:76) Avg Dump Rate (k/s) 431.4 484.5 230.9 Tape Time (hrs:min) 2:02 1:44 0:19 Tape Size (meg) 42104.6 37389.2 4715.3 Tape Used (%) 87.4 77.2 10.2 (level:#disks ...) Filesystems Taped 91 15 76 (1:76) Avg Tp Write Rate (k/s) 5873.7 6146.9 4343.1 ----------------------------------------------------- toby bluhm it support, development systems philips medical systems, cleveland ohio [EMAIL PROTECTED] 440-483-5323
