On Fri, 14 Dec 2012 08:47:59 +1300, Robert martin <[email protected]> wrote: > Hi > > One of our clients has a machine where intermittently the system crawls > to almost stop. Launching programs (like paint) takes about 2 minutes > to open. The CPU usage is low (1-3 %) but HDD usage shows at between 97
> - 100%. This situation can last 30 mins to 2 hrs before returning to > normal. > > I raise the issue here because we have traced the cause to Firebird. > When the machine is on a go slow, stopping the Firebird service fixes > the problem. Sometimes starting the service again and connecting breaks > the system again, sometimes it doesn't. I had though the issue may have > been garbage collection but we have moved from FB 2.0 super server to FB > 2.5.2 super classic and are still getting the problem. I'm pretty sure > garbage collection is supposed to be a low priority activity, right? > > The system often enters 'slow more' straight after being rebooted. > > The weird thing is that while the system is slow and the HDD shows at > around 100% use in resource monitor, the actually data throughput is > about 1 ro 5MB a sec. This is can be much higher when the system runs > normally. This made me think the HDD might be faulty but all > indications are that its not (according to a hardware technician) and of > course the problem fixes itself when stopping Firebird. > > System is > i7 quad core (8 cores in Windows) > 10 GB Ram > Windows 7 64bit > 16GB free hdd space > > Firebird 2.5.2 64bit > DB size is 2.7 GB > > > Any suggestions would be greatly appreciated. I know that there are > monitoring functions built into FB 2.5.2, should I try those? If so any > suggestions as to what to do / look for, I have not used the monitoring > tables before. The issue might be related to the Windows filesystem cache. Especially on 64 bit systems this can cause all available memory to be consumed by the cache, causing a lot of swapping and therefor slow response of the system. The firebird.conf has an option to limit the filesystem cache use. See http://www.firebirdfaq.org/faq333/ and the 2.5 releasenotes: http://www.firebirdsql.org/file/documentation/release_notes/html/rlsnotes251.html#rnfb25-fbconf-fscache Mark
