I've been having really slow backups (13 hours) when I backup a large
mail spool. I've attached a run report. There are about 1.4M files
with a compressed size of 4G. I get much better throughput (e.g.,
2,000KB/s vs 86KB/s for this job!) with other jobs.
First, does it sound as if something is wrong? I suspect the number of
files is the key thing, and the mail spool has lots of little files
(it's used by Cyrus). Is this just life when you have lots of little
files?
Second, how can I figure out what the problem is? I do have some
suspicions, but first some basics:
------------------------------------------------
everything is running on the same box
3GHz P4 with one SATA drive as the main drive and 4 older drives, one of
which is the backup target.
No noticeable CPU load or disk activity during the backup. I was
compressing, but that doesn't show up noticeably for CPU use.
Debian GNU/Linux 2.6.18 with postgresql 8.1, bacula 2.2.13.
Disk is managed by evms, using LVM.
The partion being backed up is ext3, and the backup is going to disk (a
different physical disk, IDE) using Reiser.
I am not using snapshotting because that feature is broken right now
(nothiing to do with bacula). I shut down the cyrus server during the
backup (desspite some errors in the log around my attempted shutdown, it
seemed to have worked).
My suspicion is that the TCP/IP transactions are all getting delayed
(maybe to batch for sending) in a way that usually isn't noticeable, but
is noticeable when doing lots of quick exchanges locally. Not only are
my bacula components using TCP (I think), but I'm communicating with
postgres by TCP (I couldn't get authentication working properly with
unix domain sockets).
While populating the cyrus server I also encountered very slow
transaction speeds. I think the TCP problem was the cause, though I
don't have definite confirmation. I ran multiple jobs in parallel to
populate the cyrus server to get around the slowness of the individual
parts (I think that at least rules out things like db contention or disk
contention as culprits in that case).
Unfortunately, AFAIK the tcp delay is not tuneable on Linux; it is with
BSD.
Here are some relevant parts of bacula-dir.conf:
JobDefs {
Name = "CornDefaults"
Type = Backup
Level = Incremental
Client = corn-fd
Storage = File2Storage
Messages = Standard
Pool = Default
Full Backup Pool = Full
Differential Backup Pool = Differential
Incremental Backup Pool = Incremental
Priority = 10
Write Bootstrap = "/usr/local/var/spool/bacula/%n.bsr"
}
######## Cyrus
## really this needs more care: use snapshot, dump db to ascii
Job {
Name = Cyrus
JobDefs = CornDefaults
FileSet = "Cyrus Set"
Priority = 20
Schedule = "MonthlyCycle"
Run Before Job = "super cyrus-prep"
# restart cyrus regardless of success or failure
RunScript {
RunsWhen = After
RunsOnFailure = yes
Command = "super cyrus-resume"
}
}
FileSet {
Name = "Cyrus Set"
Include {
Options {
WildFile = "*/cyrus.squat" # about 1/4 of space in spool
WildDir = "*/junk"
WildDir = "*/spam"
WildDir = "*/trash"
WildFile = "/var/lib/cyrus/proc/*"
ignorecase = yes
Exclude = yes
}
Options {
Compression = GZIP
Signature = SHA1
}
# these are on separate volumes
File = /var/spool/cyrus
File = /var/lib/cyrus
File = /etc/cyrus.conf
File = /etc/imapd.conf
}
}
--- Begin Message ---
02-Sep 01:44 corn-dir: BeforeJob: run command "super cyrus-prep"
02-Sep 01:44 corn-dir: BeforeJob: Stopping Cyrus IMAPd: cyrmaster.
02-Sep 01:44 corn-dir: BeforeJob: fatal error: must run as the Cyrus user
02-Sep 01:44 corn-dir: Start Backup JobId 118, Job=Cyrus.2007-09-02_01.05.02
02-Sep 01:44 corn-sd: Volume "Full2007-09-02_1065" previously written, moving
to end of data.
02-Sep 02:44 corn-sd: User defined maximum volume capacity 681,574,400 exceeded
on device "File2Storage" (/usr/local/var/spool/bacula).
02-Sep 02:47 corn-sd: End of medium on Volume "Full2007-09-02_1065"
Bytes=681,557,381 Blocks=10,565 at 02-Sep-2007 02:47.
02-Sep 02:47 corn-dir: Created new Volume "Full2007-09-02_1066" in catalog.
02-Sep 02:47 corn-sd: Labeled new Volume "Full2007-09-02_1066" on device
"File2Storage" (/usr/local/var/spool/bacula).
02-Sep 02:47 corn-sd: Wrote label to prelabeled Volume "Full2007-09-02_1066" on
device "File2Storage" (/usr/local/var/spool/bacula)
02-Sep 02:47 corn-sd: New volume "Full2007-09-02_1066" mounted on device
"File2Storage" (/usr/local/var/spool/bacula) at 02-Sep-2007 02:47.
02-Sep 04:39 corn-sd: User defined maximum volume capacity 681,574,400 exceeded
on device "File2Storage" (/usr/local/var/spool/bacula).
02-Sep 04:41 corn-sd: End of medium on Volume "Full2007-09-02_1066"
Bytes=681,568,759 Blocks=10,565 at 02-Sep-2007 04:41.
02-Sep 04:41 corn-dir: Created new Volume "Full2007-09-02_1067" in catalog.
02-Sep 04:41 corn-sd: Labeled new Volume "Full2007-09-02_1067" on device
"File2Storage" (/usr/local/var/spool/bacula).
02-Sep 04:41 corn-sd: Wrote label to prelabeled Volume "Full2007-09-02_1067" on
device "File2Storage" (/usr/local/var/spool/bacula)
02-Sep 04:41 corn-sd: New volume "Full2007-09-02_1067" mounted on device
"File2Storage" (/usr/local/var/spool/bacula) at 02-Sep-2007 04:41.
02-Sep 07:10 corn-sd: User defined maximum volume capacity 681,574,400 exceeded
on device "File2Storage" (/usr/local/var/spool/bacula).
02-Sep 07:13 corn-sd: End of medium on Volume "Full2007-09-02_1067"
Bytes=681,568,597 Blocks=10,565 at 02-Sep-2007 07:13.
02-Sep 07:13 corn-dir: Created new Volume "Full2007-09-02_1068" in catalog.
02-Sep 07:13 corn-sd: Labeled new Volume "Full2007-09-02_1068" on device
"File2Storage" (/usr/local/var/spool/bacula).
02-Sep 07:13 corn-sd: Wrote label to prelabeled Volume "Full2007-09-02_1068" on
device "File2Storage" (/usr/local/var/spool/bacula)
02-Sep 07:13 corn-sd: New volume "Full2007-09-02_1068" mounted on device
"File2Storage" (/usr/local/var/spool/bacula) at 02-Sep-2007 07:13.
02-Sep 09:16 corn-sd: User defined maximum volume capacity 681,574,400 exceeded
on device "File2Storage" (/usr/local/var/spool/bacula).
02-Sep 09:19 corn-sd: End of medium on Volume "Full2007-09-02_1068"
Bytes=681,568,644 Blocks=10,565 at 02-Sep-2007 09:19.
02-Sep 09:19 corn-dir: Created new Volume "Full2007-09-02_1069" in catalog.
02-Sep 09:19 corn-sd: Labeled new Volume "Full2007-09-02_1069" on device
"File2Storage" (/usr/local/var/spool/bacula).
02-Sep 09:19 corn-sd: Wrote label to prelabeled Volume "Full2007-09-02_1069" on
device "File2Storage" (/usr/local/var/spool/bacula)
02-Sep 09:19 corn-sd: New volume "Full2007-09-02_1069" mounted on device
"File2Storage" (/usr/local/var/spool/bacula) at 02-Sep-2007 09:19.
02-Sep 11:37 corn-sd: User defined maximum volume capacity 681,574,400 exceeded
on device "File2Storage" (/usr/local/var/spool/bacula).
02-Sep 11:44 corn-sd: End of medium on Volume "Full2007-09-02_1069"
Bytes=681,568,647 Blocks=10,565 at 02-Sep-2007 11:44.
02-Sep 11:44 corn-dir: Created new Volume "Full2007-09-02_1070" in catalog.
02-Sep 11:44 corn-sd: Labeled new Volume "Full2007-09-02_1070" on device
"File2Storage" (/usr/local/var/spool/bacula).
02-Sep 11:44 corn-sd: Wrote label to prelabeled Volume "Full2007-09-02_1070" on
device "File2Storage" (/usr/local/var/spool/bacula)
02-Sep 11:44 corn-sd: New volume "Full2007-09-02_1070" mounted on device
"File2Storage" (/usr/local/var/spool/bacula) at 02-Sep-2007 11:44.
02-Sep 14:27 corn-sd: User defined maximum volume capacity 681,574,400 exceeded
on device "File2Storage" (/usr/local/var/spool/bacula).
02-Sep 14:30 corn-sd: End of medium on Volume "Full2007-09-02_1070"
Bytes=681,568,780 Blocks=10,565 at 02-Sep-2007 14:30.
02-Sep 14:30 corn-dir: Created new Volume "Full2007-09-02_1071" in catalog.
02-Sep 14:30 corn-sd: Labeled new Volume "Full2007-09-02_1071" on device
"File2Storage" (/usr/local/var/spool/bacula).
02-Sep 14:30 corn-sd: Wrote label to prelabeled Volume "Full2007-09-02_1071" on
device "File2Storage" (/usr/local/var/spool/bacula)
02-Sep 14:30 corn-sd: New volume "Full2007-09-02_1071" mounted on device
"File2Storage" (/usr/local/var/spool/bacula) at 02-Sep-2007 14:30.
02-Sep 14:56 corn-fd: ClientAfterJob: run command "super cyrus-resume"
02-Sep 14:56 corn-fd: ClientAfterJob: Starting Cyrus IMAPd: cyrmaster.
02-Sep 14:56 corn-sd: Job write elapsed time = 13:11:44, Transfer rate = 90.52
K bytes/second
02-Sep 14:58 corn-dir: Bacula 2.0.3 (06Mar07): 02-Sep-2007 14:58:46
JobId: 118
Job: Cyrus.2007-09-02_01.05.02
Backup Level: Full
Client: "corn-fd" 2.0.3 (06Mar07) i486-pc-linux-gnu,debian,4.0
FileSet: "Cyrus Set" 2007-08-10 11:53:54
Pool: "Full" (From Job FullPool override)
Storage: "File2Storage" (From Job resource)
Scheduled time: 02-Sep-2007 01:05:01
Start time: 02-Sep-2007 01:44:28
End time: 02-Sep-2007 14:58:46
Elapsed time: 13 hours 14 mins 18 secs
Priority: 20
FD Files Written: 1,393,569
SD Files Written: 1,393,569
FD Bytes Written: 4,101,078,152 (4.101 GB)
SD Bytes Written: 4,300,355,440 (4.300 GB)
Rate: 86.1 KB/s
Software Compression: 64.8 %
VSS: no
Encryption: no
Volume name(s):
Full2007-09-02_1065|Full2007-09-02_1066|Full2007-09-02_1067|Full2007-09-02_1068|Full2007-09-02_1069|Full2007-09-02_1070|Full2007-09-02_1071
Volume Session Id: 3
Volume Session Time: 1188652643
Last Volume Bytes: 306,193,035 (306.1 MB)
Non-fatal FD errors: 0
SD Errors: 0
FD termination status: OK
SD termination status: OK
Termination: Backup OK
02-Sep 14:58 corn-dir: Begin pruning Jobs.
02-Sep 14:58 corn-dir: No Jobs found to prune.
02-Sep 14:58 corn-dir: Begin pruning Files.
02-Sep 14:58 corn-dir: No Files found to prune.
02-Sep 14:58 corn-dir: End auto prune.
--- End Message ---
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