Online Checkpoint Issues

We run Online with about 200 users and I have some questions that I would appreciate some comments to. The configuration is as follows: - The OS is SCO 3.2.2 - We have 9 client machines (Dell 33MHz 486) each supporting 25 users running our application, written using ESQL/C. - These clients call across the net to the server (Dell 50MHz 486 with about 2GByte disk). Thus about 200 connections over I-Star to the engine. All databases use unbuffered logging and there is a 525MByte tape to do continuous backup. Overnight a level 0 backup is done to DAT. Shared memory is about 14MByte. Checkpoint interval is 3 mins. Now the problem: Each checkpoint is taking 30-45 seconds to complete with about 3 megs of log to be written to disk. As the checkpoint starts, all currently running processes freeze. Then the disk activity takes place for 15-20 seconds and then the user tasks wake up, some much more slowly that others. Looking at the priorities of the sqlturbo processes on the server during checkpoints we find that, during normal running, they are in the mid 20's but by the end of the checkpoint their priorities have dropped (risen?) to 65-70. I suppose this accounts for their slowness in re-starting. How can I reduce or preferably eliminate the pause in use? Some solutions have been suggested: 1) Get a cacheing disk controller (and a UPS) to allow Online to think it has flushed the logs quicker. 2) Get a SparcServer. 3) Become a Monk so its somebody else's problem. Any thoughts would be much appreciated. -- Paul Mahoney, X-Act Solutions Limited smail: 20 Shipley Lane, Cooden, Bexhill-on-Sea, East Sussex, TN39 3SR email: ptm@xact.demon.co.uk ... pmahoney@cix.compulink.co.uk phone: +44 424 3 6368