We currently have an IBM DS4300 Dual Controller Fibre SAN. It is a good box, but getting pretty old. It came with 256MB of cache per controller.
Recently we replaced the batteries in one of the controllers and noticed that the cache is a DDR PC2100 ECC DIMM. Of course, we are thinking about how cheap this RAM is now and is there any good reason we can't upgrade the RAM.
IBM used to have a "Turbo" upgrade to this box that doubled the cache and had a bunch of software features for about 10K USD. Since that product has been end-of-lifed, I don't think we can get that upgrade and we don't need the software upgrades (FlashCopy, StorageCopy, etc).
Besides the obvious potential warranty issue, what if any issues would we expect to see if attempting to put 2 - 1GB DIMMS in this unit?
Any other things I am missing here?
EDIT: Memory label:
Samsung
CN 0433
PC2100U-25331-A1
M381L3223ETM-CB0
256MB DDR PC2100 CL2.5 ECC
Just in case someone finds this later, we were able to update the Cache memory without trouble. Noticed a huge improvement in speed (as expected), especially when writing files to the SAN.
Just been googling around that part and it's a very straightforward off-the-shelf item, certainly if you go for a bigger one it's fit and work from an electronic perspective with no problem. The issue you may have is that the firmware might not see it or use it, but it's not a bit cost so why not give it a go, the worst thing that can happen is it just doesn't work.
Good luck.