Temporary directory (/tmp) size


I’m setting up a backupserver and I’m a newbie to urbackup (and to backup servers, actually). I choose zfs on FreeBSD. My test server is up and working properly. I now need to order disks for the production server. I would like to put the filesystem on a ssd but I fail to understand what size should I pick up.

In the Administration manual I read (section 11.7.1):

“First setup the server such that the temporary directory (/tmp) is on a sufficiently large performant file system”

Now, how large is “sufficiently large”?
I need to backup a couple of servers which take about 500GB of disk space each.


The only place bigger drives ever hurt was the budget.

Could you not try with /tmp on your main file-system & monitor how big it gets on some trial runs with your test server to inform the decision?

I had my temp dir on a 128 GB dedicated drive & was getting low space warnings from Windows till I set a disk quota, so while unqualified my instinct says don’t put /tmp on anything less than a 250 ish GB drive. My data store itself is slow as molasses in January though, only USB3 DAS, so maybe things were piling up.

I was dealing with more data than you, but the bulk arriving slowly by domestic broadband & a venerable PC on the LAN which still has a 10/100 NIC.

I think this might be more of a ramble than actual help, sorry if that’s the case.

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That advise is a bit outdated. The old behaviour (where files are loaded to tmp space first) can be re-enabled by the settings in 8.5.1 Enabling temporary file buffers. You probably don’t want to do that if your backup storage performance is high, such as yours.

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@Bearded_Blunder thank you. Actually it’s very useful.

@uroni thanks. I now understand why I wasn’t experiencing serious issues in my test environment (quite limited indeed).