I have been trying to improve my backup system by using the new (5.0) feature 
of Maximum concurrent Jobs on storage devices, and would appreciate some hints 
on how to get good performance with my configuration. I'm using bacula 5.0.3 on 
CentOS 5. The concurrent configuration works beautifully, it is just 
unexpectedly slow (for those who came across this post by Google, some hints 
are below; I had to guess on some configurations since I didn't find all the 
details for this feature in the documentation).

My problem is that the performance is poor. For testing, I did a full backup of 
two Linux servers with around 2.5-3.5 GB of data each. Backed up sequentially, 
each backup took about 6-10 minutes. When backing them up concurrently, the 
same backup took well over 1 hour!

I am backing up to file volumes. The file volumes are located on an NFS server 
connected with Gigabit Ethernet. The NFS server is a FreeNAS 7 box, which is 
usually blazingly fast.

The two Linux boxes I am backing up are actually virtual machines on VMWare 
ESXi. Director, FD and SD are all on the same physical hardware.

So how would I go about tracking down what slows down the performance so 
dramatically?


And, unrelated to my question, here are the hints to make "maximum concurrent 
jobs on device" work:
You need to make changes to both the bacula-sd.conf and the bacula-dir.conf 
file, as follows:

In bacula-sd.conf:

- add more devices. They need to all be identical except for the name and the 
device itself. Each device should be configured with Maximum concurrent jobs=1. 
For instance, for a file-based device, I use this as the first device (for the 
second and third, I just changed Name and Archive Device):

Device {
  Name = BACKUP1-dir1
  Media Type = File
  Device Type = File
  Archive Device = /misc/BACKUP1/bacula1
  LabelMedia = yes;                   # lets Bacula label unlabeled media
  Random Access = Yes;
  AutomaticMount = yes;               # when device opened, read it
  RemovableMedia = no;
  AlwaysOpen = yes;
  Maximum Concurrent Jobs = 1;
}

The storage resource should have
  Maximum Concurrent Jobs=3

This should match the number of devices you use exactly.

What had tripped me up initially was that in bacula-dir.conf, you need to 
modify the storage resource, as well. It must list all three devices. Also, 
again set Maximum Concurrent Jobs to exactly the number of devices (if you set 
it to a higher value, your jobs will be blocked by the SD, or worse, by the 
device itself. You don't want that since it may cause timeouts if you have Run 
Before scripts).

Storage {
  Name = Disk1
# Do not use "localhost" here
  Address = baculasd.mydomain # N.B. Use a fully qualified name here
  SDPort = 9103
  Password = "XXXXXXX"
  Device = BACKUP1-dir1
  Device = BACKUP1-dir2
  Device = BACKUP1-dir3
  Media Type = File
  Maximum Concurrent Jobs = 3
}



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