MOLTA@VAXB.ACS.UNT.EDU (01/10/90)
>Hi. We're looking adding about 640MB of diskspace and upgrading to ver. >2.15 SFT on our existing LAN which looks like this at the moment. >IBM Token Ring topology >Novell 286B fileserver running SFT Netware 286 II ver. 2.0a >183 MB of disk storage >2 MB of RAM memory >I've got a couple of questions... >1. How much more memory are we going to need (if any) to accomadate the > increase in directory caching? A rule of thumb that I use is 4 KBytes of RAM for every megabyte of disk space for disk cache. For 640 Megabytes of disk, that would add up to a little over 2.5 Megabytes. In addition, you'll have to factor in RAM for directory caching, which is difficult to estimate without knowing more about your environment (for reference, Novell allocates 5632 directory entries, or 176K RAM, by default for an 80 Megabyte drive---figure at least 1 Megabyte for your environment), communications buffers, file control blocks, file locking, FATs, Lan Drivers, and the OS itself. Overall, I think you're looking at a minimum of 4 Megabytes, and 8 Megabytes would probably be better. Of course, all of this depends a whole lot on your applications. If you're using the server to store lots of word processing files, you may not even need to cache those volumes. If you've got lots of database files or a wide variety of different applications that are loaded from the server, it'll really improve performance to have more memory. With memory costing under $100 per megabyte, it's probably a good idea to buy lots of it. >2. Would it be better to get one 650MB drive or break it up into two 320MB > drives? I think this depends on your future plans and how much money you've got. The cost per Megabyte will probably be about 25% less if you go with the 650 MB drive and you will have room for another drive in the server itself. On the other hand, if you don't ever plan to expand your disk space, buying two 320s would have the obvious advantage that if one crashed, you could still limp along until you got it repaired. As far as performance is concerned, I don't think you'll see any improvements with two 320 MB ESDIs compared to 1 640 MB ESDI since they'll both share the same channel. If you go SCSI with two Novell or Procomp DCBs, you could run the two 320s on different channels and see some performance benefits. >3. Would there be any advantages to switching the operating system > and all the files to the larger disk and using the existing > 183MB the second drive on the new controller? If the 183 MB drive is compatible with the new controller and the drive still has some life on it, why trash it? If you keep the 183, you'll probably want to go with the single 640 drive. Hope all this helps a little. Dave Molta University of North Texas