On 01.03.2019 1:50, Adam Nielsen wrote:
I'm backing up 2 servers with Bacula, one with Windows 2016, the other
one with CentOS. The hardware is described below. The Windows server is
much more powerful than the Linux server in all respects, and should
theoretically deliver data to the Bacula server at a much higher rate.
But in reality, the Linux server delivers data about 7 times faster over
the network, than the Windows server.
It's very hard to say, because many small files will take longer to
transfer than a couple of large ones, and if there is other machine
activity reading or writing from the disk at the time then this can
sometimes slow the transfer speed dramatically, at least with magnetic
disks.
You could try to create a large file on both machines, say 10-20GB, and
then try to back up just that one file. This should eliminate one
variable (many vs few files) and give you a better idea how different
the machines are.
Perhaps you could also run some disk speed tests locally on each
machine. Linux has hdparm included in most distros, but I'm not sure of
a Windows equivalent although I'm sure there are many out there.
Because you only have a single average transfer speed for the Windows
machine, it's conceivable that a failing disk will work fine for a
while but then become stuck on a few sectors and sit there for even a
few minutes retrying the read operation before continuing. This could
result in a slow overall transfer rate but a fast speed test, if the
speed test doesn't read any of the failing data areas. If the speed
test comes back good, then it might be worth trying to find some SMART
tools for your disk/controller which can usually query the drives for
the number of errors they've been encountering recently. If those are
high for one drive then that could explain what's going on.
Cheers,
Adam.
Hi Adam,
Thanks for your suggestions. It is true that the backup from the Windows
server is mostly user profiles and (normal office) documents, while from
the Linux server it's CAD and publishing data, where the files mostly
are quite large. I have excluded the disk subsystem on the Windows
server, as it is a true SAS RAID (not fake RAID) controller, where the
RAID5 configuration is "overpopulated". A bad disk here should not have
any impact on the transfer speed. I did run diagnostics on the RAID
controller a month ago, and there are no error indications. The backups
are running in the night, when there is no user activity on the network.
I'll give the large file approach a try during the weekend, and see
where it gets me.
Best regards,
Peter
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