Retrospect and ASIP

Since your freeze is happening during times of low use, but after a backup, the problem is more likely to be a memory conflict between ASIP and Retrospect. If your lockups happened during high client activity usage, then I'd be looking at the RAM, cabling, or hard disk driver software.

Retrospect will expand in memory usage dynamically over time, similar to how the ASIP Cache expands over time. Because your crash doesn't happen every night, you are likely having a problem with Retrospect's temp memory overlapping ASIP's temporary Cache memory as they each build up over time.

Solution?
I have Retrospect running on four different ASIP servers, and none of them have these lockups.

What's the secret?

1. Do not use the checkbox in ASIP Easy Setup, to automatically start ASIP at startup. OR you can leave it checked and put an alias to Retrospect into the Startup folder so that it starts up before ASIP.
2.  Adjust Retrospect's memory requirements. Default memory is about 3 megs. Boost this to at least 5 megs, and 10 megs is preferable.
3. Make sure you have lots of RAM in your ASIP server. I've found 96 to be minimum. I've learned that ASIP is much more stable when given lots of RAM.
4. Put an alias of Retrospect, and an alias of ASIP Web & File Server Extension, in the Startup Items folder. Make sure you put a space in front of the Retrospect alias name, so it loads BEFORE the ASIP server extension. Note: if in step (1), you used the checkbox to startup ASIP, then you do not need an alias to ASIP here.
5. If you run any other software on your server, put an alias of these apps in the Startup Items folder, and add a space for each of them as well. You want any other apps on the server to load before ASIP.
6. Set Retrospect's preferences so it does not quit after execution of a script. You want to leave it running all of the time.

The goal is to get Retrospect loaded before ASIP, so the ever-expanding ASIP cache doesn't bump into Retrospect's memory space. By loading Retrospect before ASIP, and giving it extra RAM, you give Retrospect a nice clean space to do its work, and the ASIP cache will never expand into the temp memory space that Retrospect uses.

Note from Brad Suinn
There is some hidden feature inside of Retrospect where you can make it stop using Temp Memory. Hold down the Option key while clicking the Preferences button under the Special tab. By not using temp memory, it will slow down Retrospect, but you can compensate by increasing the memory assigned to Retrospect using the "Get info" panels. By doing this, then you keep ASIP and Retrospect from "fighting" over memory and that should make things more stable.