FM Server 8 on a Mac Mini crashes

[Jimery]

Hi all,

I have been having a problem with our FM Server. The computer freezes at irregular intervals, requiring a forced reboot. I have searched various forums and have yet to find an answer. In the course of looking through these forums, I read that someone likes mysteries...so here's one that has me stumped.

First, some details

Mac Mini

1.42 GHz Power PC G4

1 GB RAM

External FireWire drive for backups

UPS

dedicated FileMaker server

Mac OS 10.4.6

FM Server 8.0v2

hosting 50 files

total size 600 MB

for 20 local clients (all 8.0v2)

64 MB RAM for db cache

The problem we are having is that the machine freezes almost weekly but not at any predictable time or date. Sometimes, this happens in the middle of the night when no clients are connected to the server. The first sign of this is usually when FM becomes unresponsive to clients with the spinning beachball.

When this happens, the mouse still responds on the server. I can sometimes move windows in the Finder and between various screens in FM Server Admin. Trying to open an app or select a menu item in FM Server Admin or do just about anything else, causes the machine to become unresponsive (although the mouse still moves the cursor). I am still able to ping the mini.

I have tried reinstalling and upgrading the system software and FM server from scratch. Crash logs have not provided any useful clues and are not being written from FM Server when this happens. I had the macine into the Apple store recently and their hardware tests could not find anything wrong with it.

I have read some posts that say do not use a Mac Mini as a server and others that say it works fine. The drive speed seems to be an issue but does not explain why it would crash in the middle of the night when nothing is happening.

I am wondering if anyone has any ideas that would explain this or help me to figure out what is going on. I would appreciate any help you can offer. Thanks.

[xochi]

I use a mac mini with 10.4.6 and it's 100% reliable.

However, I used to have the same problems you are describing. The solutions were (A) turn of ALL energy saving options, particularly the one about spinning down hard drives, and (: upgrade to 10.4.6 (I found early some 10.3s and 10.4s were unstable).

My detailed experiences here: http://fmforums.com/forum/showtopic.php?tid/173061/post/206382/hl//#206382

[xochi]

Mac OS 10.4.6

FM Server 8.0v2

hosting 50 files

total size 600 MB

for 20 local clients (all 8.0v2)

64 MB RAM for db cache

1. Upgrade to 8.0v3. It's probably not related to your freezes, but 8.0v2 has poor performance and indexing bug.

2. Any reason you have the RAM cache set so low? You can get about 220MB on a mac mini with 1GB of RAM. RAM cache is your friend!

[Jimery]

Thanks for the suggestion Xochi. I thought I had done this already but I just noticed there are separate energy saver settings for the UPS...one of which is put hd to sleep whenever possible. I just unchecked this and turned off all other energy saver settings other than put the display to sleep.

[Jimery]

2. Any reason you have the RAM cache set so low? You can get about 220MB on a mac mini with 1GB of RAM. RAM cache is your friend!

No except that I recently upgraded the RAM on the machine from 512 MB to 1 GB and a 64 MB cache was more appropriate when the machine had only 512 MBs of RAM.

Even with the RAM cache so low, I am still getting a cache hit % of 99-100. I will increase it and see if it helps. Thanks.

Edited May 19, 2006 by Guest

[xochi]

2. Any reason you have the RAM cache set so low? You can get about 220MB on a mac mini with 1GB of RAM. RAM cache is your friend!

With the caveat that if you are crashing, ever, higher RAM cache may increase the amount of corruption (more uncached data sitting in RAM was lost).

But really, you should expect a 100% reliable FMServer8v3. Any crashing means something is seriously wrong.

[Steven H. Blackwell]

This could also be an issue with the OS and the chip set. Please keep us posted on your progress fixing this.

Steven

[xochi]

More details on my situation: When the server locked up, it was not actually fmserverd which crashed -- it appeared as if the networking stack was getting hosed. ARD would drop, and pinging would stop working, but if you connected a real keyboard, the screen was alive and the cursor was working. However, you couldnt' do much, as any attempt to access a disk drive or network would give a spinning beachball. I'm pretty sure this was a late 10.3 and early 10.4 bug, which shouldn't be showing up in 10.4.6.

Many people thought it was due to the dns daemon locking up. Search the discussions.apple.com forums for keywords such as "lookupd crash".

So while similar, it does sound like you and I had somewhat different experiences.

Prior to that, I would get immediate system lockups which were due to booting from an external firewire drive and leaving some of the energy saver features turned on.

Final thoughts -- it does seem like macs these days have grown more picky about RAM quality. If you have the old 256 or 512 ram stick, you might want to try that?

If you do solve it, we'd love to know what worked.

[xochi]

No except that I recently upgraded the RAM on the machine from 512 MB to 1 GB and a 64 MB cache was more appropriate when the machine had only 512 MBs of RAM.

Even with the RAM cache so low, I am still getting a cache hit % of 99-100. I will increase it and see if it helps. Thanks.

OS X does really aggressive & high quality READ cacheing, so if your primary operation is reading data (rather than changing it), you'll see pretty darn good performance anyway. The data is still cached in RAM, just OSX is doing it instead of filemaker. My experience is that FMS RAM cache really earns it's keep when you are doing large-scale updates of data. In that case, it appears to me that the changes are cached in RAM, and later flushed to disk.

One weird behavior ("bug") I've seen is that the setting "flush cache when idle" seems to be very liberal with the definition of "idle". E.g. I've seen it do cache flushing in the middle of a looping script, which is generally the exact time you don't want cache flushing. In those cases, setting a value (30 minutes) can actually increase performance a bit.

[Steven H. Blackwell]

OK, on FileMaker Server, the flush of cache is continuous. The time setting is for the [color:red] interval over which that flush occurs, not the frequency with which it occurs.

Steven

[Jimery]

Many people thought it was due to the dns daemon locking up. Search the discussions.apple.com forums for keywords such as "lookupd crash".

Final thoughts -- it does seem like macs these days have grown more picky about RAM quality. If you have the old 256 or 512 ram stick, you might want to try that?

If you do solve it, we'd love to know what worked.

The RAM was upgraded by our local Apple store in the hopes of avoiding bad RAM issues. The new chip could be bad but crashes occurred both before and after the RAM upgrade.

The lookupd process sounds promising. Sounds like lookupd problems interfere with crash logs being written which fits our pattern. I can think of two things that might contribute to this...there is an attached FireWire drive and we have an NFS server on our network. The Mini is not set up as an NFS client but I think it could be receiving signals from the NFS Server. I am probably reaching here but maybe it will lead to the answer.

The server went down again this morning so I took the opportunity to upgrade to FM Server 8.0v3.

If/when I get this figured out, I will certainly post the info here. Thanks.

[xochi]

OK, on FileMaker Server, the flush of cache is continuous. The time setting is for the [color:red] interval over which that flush occurs, not the frequency with which it occurs.

Steven

Good point. Any idea how the interaction between the Cache Idle Flush settings on Client vs. Server work? Are they independent?

[Steven H. Blackwell]

Any idea how the interaction between the Cache Idle Flush settings on Client vs. Server work? Are they independent?

They essentially bear no relationship to one another. it is conceivable that a flush cache on a client could prompt network activity going back to the server.

Steven

[Vaughan]

So the "Flush Cache to Disk" script step instructs the *client* to flush its cache, not the server?

[Genx]

Ummm, this is one thing i've never even thought about. Could someone please explain to me what the cache is and what effect flushing it to disk has?

Cheers,

~Genx

[Steven H. Blackwell]

So the "Flush Cache to Disk" script step instructs the *client* to flush its cache, not the server?

Correct, it instructs the client, not the Server.

Steven

[Steven H. Blackwell]

In a Server hosted file, the cache is the portion of the local client RAM memory where FMP writes and reads information. The flush cache writes that information out to the temp file on the client hard drive. Network packet transfers also play a role in this sending information back and forth between the FMP client and the FM Server.

HTH

Steven

[Genx]

Thanks Steven. Just to make sure i understand:

Filemaker reads / writes info to ram because its quicker.. but ram is limited and gets used up, so every once in a while it has to be flushed to hd?

Cheers

[xochi]

Thanks Steven. Just to make sure i understand:

Filemaker reads / writes info to ram because its quicker.. but ram is limited and gets used up, so every once in a while it has to be flushed to hd?

Cheers

Correct -- accessing data in RAM is much much faster than writing to/from the hard disk (10, 100, or 1000 times faster). However, you have more disk than RAM, so sometimes you run out.

The other issue is that RAM is volatile, meaning when the power is off, the data is gone. Therefore, you don't want to keep changed data in RAM indefinitely, as a power outage or crash would wipe them out.

Where this gets complicated is when using filemaker in a client/server setup -- in this case, both the client & server maintain RAM caches. Actually, it's even more complicated than that, since the operating system itself generally has it's own cache.

[Genx]

So does the cache have to be flushed manually on the client side or will FM do it itself when it's full?

Cheers for the explanation btw.

~Genx

[Steven H. Blackwell]

It does not have to be manualy flushed. BTW, if this is FMP 8 set the amount of RAM reserved for cache to be 12 MB not the default 8 MB.

Steven

[Genx]

Will do

Cheers Steven,

~Genx