I don't think that LARGECOMMBUFFERS and USELARGEBUFFERS are related, at least not directly.
In general, USELARGEBUFFERS YES on the TSM server helps improve server throughput and efficiency for large files. I've seen no suggestion to set it to NO, even on Windows. he LARGECOMMBUFFERS client option can help improve client throughput/efficiency, but I'm pretty sure that it relies on the OS disk read-ahead ability to achieve that performance improvement (other factors include amount of system memory, disk speed, etc.). On Windows, our testing has found that, especially for small files, setting LARGECOMMBUFFERS YES doesn't help, and is in fact, detrimental. For example, I just did a little test myself on Windos 2000. I have a test directory containing 62 files, each file being exactly 100,000 bytes in size. WIth LARGECOMMBUFFERS NO, the backup took around 7 seconds. With LARGECOMMBUFFERS YES, the backup took around 12 seconds. Generally speaking, there are very few absolutes in life, and TSM options are no exception (if they were, we would just hard-code the values and not make them options). Sometimes bigger is not always better. You should experiment with which settings work best for your environment. In some cases, such as very fast systems with lots of memory, very fast disks, and large average file sizes, LARGECOMMBUFFERS YES might be helpful; but to start, I'd suggest LARGECOMMBUFFERS NO for Windows. On AIX, our testing indicates that setting it to YES is usually a good idea, so that's why it's default is YES. I have no experience in testing these settings on the other platforms, and I am not a performance guru, so in lieu of anything else, go with the settings that you are accustomed to. But... it might not be a bad idea ot run some benchmarks with different settings, just to validate what you are doing. Regards, Andy Andy Raibeck IBM Software Group Tivoli Storage Manager Client Development Internal Notes e-mail: Andrew Raibeck/Tucson/IBM@IBMUS Internet e-mail: [EMAIL PROTECTED] The only dumb question is the one that goes unasked. The command line is your friend. "Good enough" is the enemy of excellence. Josuha wrote: That is a new one on me. Per the last Performance Tuning Guide, a bit long in the tooth, LARGECOMMBUFFERS was recommended Yes. So let me get this straight: Windows clients - set LARGECOMMBUFFERS to No UNIX, Novelll, etc. - set LARGECOMMBUFFERS to Yes How about UNIX clients backing up to a TSM Server on Windows? ........... Neil wrote: Andy You say we should be settting LargeCommBuffers to No (the default) on Windows clients. How does this relate - if at all - to the UseLargeBuffers server option, the default for which is Yes? Should we be changing this if we are running TSM Server on NT?
