The original post: /r/datahoarder by /u/fgt67cam on 2024-05-19 17:00:22.
I recently purchased a LTO-5 tape drive to back up some HDDs. The drive itself is working and connected via FC using a QLE2562 PCI-E.
My plan was to original create a SAS RAID 0 to temp store the files being written to tape from the offline HDDs but I've had issues with the P410 controller not working so for now will have to connect the offline SATA drives to the server (Proliant ML330 G6).
The drives I'm using aren't fast (ST3500312CS) but I did a read speed test using dd if=mytestfile of=/dev/null bs=1M count=1024 and they're getting around 80-90/MBs and online speed results show roughly the same. It's not fast but should be enough to do one backup copy before trying to fix the SAS issue.
I've timed how long it's taking for it to do each file and the results:
File 1 - 309 seconds - 10,045,430,602 bytes ~32.5/MBs
File 2 - 291 seconds - 13,597,137,146 bytes ~46.7/MBs
File 3 - 302 seconds - 13,967,991,165 bytes ~46.2/MBs
File 4 - 94 seconds - 4,526,005,392 bytes ~48.1/MBs
File 5 - 113 seconds - 5,139,777,083 bytes ~45.4/MBs
File 6 - 107 seconds - 4,917,953,848 bytes ~45.9/MBs
As first it seemed like the culprit was the HDDs so I installed a Samsung EVO 850. It scored 226/MBs with the same read test so much faster than the HDDs. I then had it write a 34GB file to tape and it took 528 seconds (not including tape rewind time) coming in at ~69.1/MBs which is still slow so I don't think the bottle neck is the SATA drives. The FC card is showing the link speed as 8Gbps and even if it was 1Gbps it's still too slow so I don't think it could be that. All that's left is the tape drive or Debian/drivers/software. I'm using "tar cvf /dev/st0" to write data to the tape.