Bacula-users

[Bacula-users] slow copy job from disk to LTO-6 (speed issue)

2017-03-25 23:10:29
Subject: [Bacula-users] slow copy job from disk to LTO-6 (speed issue)
From: Caribe Schreiber <caribe AT auctionharmony DOT com>
To: bacula-users AT lists.sourceforge DOT net
Date: Sat, 25 Mar 2017 22:09:16 -0500
Geesh...somehow the line endings got all munched up on my console output in the last email.  Hopefully this is actually readable.  Sorry for the double post!

~Caribe

Here's the output for a moderate size copy job going from local disk (FileChgr1-Dev1) to the SAS attached LTO-6 tape (Drive-1) showing the Drive -1 speed as 23.22MB/s:

backup-sd JobId 64 Sending spooled attrs to the Director. Despooling 2,615 bytes ...

Elapsed time=02:03:24, Transfer rate=7.346 M Bytes/second backup-dir JobId 64 No Files found to prune. End auto prune.  Bacula backup-dir 7.4.4 (202Sep16):     Build OS: x86_64-pc-linux-gnu gentoo     JobId: 64 Job: BackupImage.2017-03-24_21.45.00_45     Backup Level: Full Client: "primary-fd" 7.4.4 (202Sep16) x86_64-pc-linux-gnu,gentoo     FileSet: "BackupFileSet" 2017-03-24 21:45:00     Pool: "file.full" (From Job resource)     Catalog: "MyCatalog" (From Client resource)     Storage: "file" (From Pool resource)     Scheduled time: 24-Mar-2017 21:45:00     Start time: 25-Mar-2017 00:12:38     End time: 25-Mar-2017 02:16:03     Elapsed time: 2 hours 3 mins 25 secs     Priority: 13     FD Files Written: 7     SD Files Written: 7     FD Bytes Written: 54,391,511,056 (54.39 GB)     SD Bytes Written: 54,391,515,157 (54.39 GB)     Rate: 7345.2 KB/s     Software Compression: 57.8% 2.4:1     Snapshot/VSS: no     Encryption: yes     Accurate: no     Volume name(s): full-Vol-0024|full-Vol-0029     Volume Session Id: 49     Volume Session Time: 1490104159     Last Volume Bytes: 22,911,377,270 (22.91 GB)     Non-fatal FD errors: 0     SD Errors: 0     FD termination status: OK     SD termination status: OK     Termination: Backup OK Begin pruning Jobs older than 6 months . No Jobs found to prune. Begin pruning Files. backup-dir Using Device "Drive-1" to write. backup-sd Elapsed time=00:39:02, Transfer rate=23.22 M Bytes/second backup-sd Alert: smartctl 6.4 2015-06-04 r4109 [x86_64-linux-4.4.39-gentoo] (local build) Alert: Copyright (C) 2002-15, Bruce Allen, Christian Franke, www.smartmontools.org Alert: TapeAlert: OK Alert: === START OF READ SMART DATA SECTION === Alert: Alert: Error Counter logging not supported backup-sd Sending spooled attrs to the Director. Despooling 2,615 bytes ... Alert: Last n error events log page Alert: Alert:

I'm able to get good write speeds to the LTO-6 drive with btape as shown here:
 
Wrote block=100000, file,blk=1,99999 VolBytes=6,451,135,488 rate=157.3 MB/s
Wrote block=105000, file,blk=1,104999 VolBytes=6,773,695,488 rate=157.5 MB/s
Wrote block=110000, file,blk=1,109999 VolBytes=7,096,255,488 rate=157.6 MB/s
Wrote block=115000, file,blk=1,114999 VolBytes=7,418,815,488 rate=161.2 MB/s
Wrote block=120000, file,blk=1,119999 VolBytes=7,741,375,488 rate=161.2 MB/s
Wrote block=125000, file,blk=1,124999 VolBytes=8,063,935,488 rate=161.2 MB/s
Wrote block=130000, file,blk=1,129999 VolBytes=8,386,495,488 rate=161.2 MB/s
I'm also able to get good read speeds off the drive array as shown by bonnie++ here:

backup ~ # bonnie++ -u root
Using uid:0, gid:0.
Writing a byte at a time...done
Writing intelligently...done
Rewriting...done
Reading a byte at a time...done
Reading intelligently...done
start 'em...done...done...done...done...done...
Create files in sequential order...done.
Stat files in sequential order...done.
Delete files in sequential order...done.
Create files in random order...done.
Stat files in random order...done.
Delete files in random order...done.
Version  1.97       ------Sequential Output------ --Sequential Input- --Random-
Concurrency   1     -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec %CP
   backup      126G  1211  97 601130  47 240240  17  5506  94 759982  22 698.1  10
Latency              9305us     710ms     646ms   15409us     276ms     519ms
Version  1.97       ------Sequential Create------ --------Random Create--------
   backup           -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
              files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
                 16 16535  15 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++
Latency               385us     360us     714us     383us     370us     345us
1.97,1.97,backup,1,1490480328,126G,,1211,97,601130,47,240240,17,5506,94,759982,22,698.1,10,16,,,,,16535,15,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++,9305us,710ms,646ms,15409us,276ms,519ms,385us,360us,714us,383us,370us,345us

And it's pretty fast using dd to read a bacula file from the job as well:
backup bacula # dd if=full-Vol-0029 of=/dev/null bs=4M
12799+1 records in
12799+1 records out
53687083817 bytes (54 GB, 50 GiB) copied, 111.637 s, 481 MB/s

Here's my tape drive and local file storage config in the bacula-sd.conf:
#
# A file changer for disk based backups
#
Autochanger {
  Name = FileChgr1
  Device = FileChgr1-Dev1
  Changer Command = ""
  Changer Device = /dev/null
}

Device {
  Name = FileChgr1-Dev1
  Media Type = file
  Archive Device = /home/backups/bacula
  LabelMedia = yes;                   # lets Bacula label unlabeled media
  Random Access = Yes;
  AutomaticMount = yes;               # when device opened, read it
  RemovableMedia = no;
  AlwaysOpen = no;
  Maximum Concurrent Jobs = 5
}



#
# An HP 1/8 autochanger device with one drive
#
Autochanger {
  Name = AutochangerHP
  Device = Drive-1
  Changer Command = "/usr/libexec/bacula/mtx-changer %c %o %S %a %d"
  Changer Device = /dev/sg3
}

Device {
  Name = Drive-1                      #
  Media Type = LTO-6
  Archive Device = /dev/nst0
  AutomaticMount = yes;               # when device opened, read it
  AlwaysOpen = yes;
  RemovableMedia = yes;
  RandomAccess = no;
  AutoChanger = yes
  Maximum File Size = 10GB
  Alert Command = "sh -c 'smartctl -H -l error %c'"
}
I'm a little stumped about why the raw hardware read/write speeds are so different from the bacula copy job speeds. I'm hoping the collective wisdom of the list can give me some ideas on other places to look for speed issues or config changes so that I don't prematurely wear out this drive head with shoe-shining (of course...faster backups are always welcome too!).
Thanks in advance!
~Caribe
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