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I'm reposting this message since it didn't appear in the list the first time I sent it... Sorry if it's a duplicate. Hi. Well in fact I have a case where this didn't work out. My friend ordered this upgrade for his SP Xserve and when they installed it, everything went fine except that the system didn't recognize the second processor at all -- it was running in SP mode like nothing has happened. I'm going to clarify some points such as whether there's any different in hardware config from the server's point of view (would probably indicate whether the firmware or software is to blame) in the upcoming days and post more info. So that's why I asked. On an unrelated note, SP 2.0 Ghz going to be retired? Why'd you want to replace it? Russell, maybe investing in a G5 cluster node makes more sense then? And oh, the same people who unsuccessfully tried to instal a processor module also tried to install a spare hard drive into an Apple Drive module (with a faulty disk) that was a part of an Apple RAID system, and this endeavour failed as well - this hardware "hack" wasn't recognized by the RAID at all. Was also a concern to me because I had an idea of fooling everyone (heh heh!) and purchasing another 80 Gigabyte module just to take it apart and replace the disk with a 400-500 Gigabyte one. Luckily common sense prevailed in the end and I bought the real one. Buck Message: 21 Date: Thu, 05 Jan 2006 18:39:22 -0600 From: Dave Schroeder <email@hidden> Subject: Re: Single-proc. G5 to Dual-proc G5 To: Buckie Joe <email@hidden> Cc: email@hidden Message-ID: <email@hidden">email@hidden> Content-Type: text/plain; format=flowed; delsp=yes; charset=US-ASCII If you can in fact accomplish this from a hardware standpoint, no OS reinstall is necessary. However, you will likely not be able to add a processor to a single processor Xserve. - Dave On Jan 5, 2006, at 6:08 PM, Buckie Joe wrote: My question is - has anyone tried that? Is it possible to install an additional processor card into a G5 Xserve that came in Single-processor configuration? Will it require an OS reinstall, or the system (OS, firmware) will recognize this and reconfigure itself appropriately? Or is the config somehow hardcoded in firmware in Xserves? Dave, I'm not sure you are right here about not likely being able to add a second processor, because I've been seriously considering that for our Xserve G5 if the load gets high. Looks very possible. Here's my analysis (at least for 2.0 GHz SP Xserve G5 vs. dual processor, January 2005 version 2 motherboard that supports 2 GB DDR DIMM sticks; haven't done the detailed check for any other version than our server): (1) the Xserve spare parts kit for the 2.0 GHz SP Xserve G5 is the same as the Xserve spare parts kit for the 2.3 GHz DP Xserve G5, which means that they have the same motherboard - Apple part # 661-3307 - without jumpers that might need to be changed to adjust clock speed, etc. The 2.0 GHz SP Xserve G5 just has a plastic cover over the second socket. See, e.g.: All clocking for the processor module is done on/by the processor module, not the motherboard. The fact that the motherboard is the same for SP/DP seems to indicate that there isn't even any config info in the nvram. But there will/can be issues with the serial number and model number not matching the configuration recorded at Apple support. Point being, the system does a boot-time configuration determination of its environment. The instructions for replacing the logic board are on Apple's "Do it yourself" replacement site, and don't mention any jumper settings, etc., that have to be changed for SP/DP use: (2) The 2.3 GHz Xserve G5 processor module is Apple Part # 661-3278. See, e.g.: (3) The 2.0 GHz Xserve G5 processor module is Apple Part # 661-3152. See, e.g.: (4) The instructions for replacing the processor module are given here, and it just involves unscrewing/screwing some screws: The part numbers and costs above for the processor module and logic board are from simple poking around at macsupportstore.com, which is an Apple Authorized Reseller and repair depot, and the processor module replacement instructions are on Apple's "Do it yourself" replacement site at So none of this stuff is covered by NDA. Here are my concerns: (a) obviously, this voids your AppleCare support contract and creates an unsupported configuration. That's a concern to us, but would be a non-concern if we were at the end of the 3-year support contract and just needed to buy some time and get a little more processing power rather than do a wholesale processor replacement. I really wish that Apple made it possible to purchase a supplemental server support contract for additional years, but they won't sell support past 3 years. When you are a tiny business like we are, with only one Xserve, you have a very different view than a large organization such as yours, Dave, which can look at the Xserves as commodities. (b) Apple manufacturing has only tested the single processor configuration of your Xserve G5, so there may be unknown/untested problems with the unused processor socket that don't show up in a single processor configuration but that would appear if a second processor were added. Untested, so unknown. (c) the OS cache files that are built on the first boot - this used to be a source of problems if, for example, you took a full running system disk image created on one type/vintage machine over to another, and I seem to recall that there were some instructions on the asr man page (regarding creation of netboot images) that certain files need to be deleted, because some people have remarked about this in the past. May not be a problem any more with 10.4.x, but I don't know; Dave, you indicate that this is a non-issue, and you are more knowledgeable than I am on this point, so I bow to your judgement. I think that Mike Bombich had a discussion of these issues on his Carbon Copy Cloner site where he discussed the underlying stuff that his script does when cloning, in that not everything is copied over. But, worst case, this could be solved by a reinstall of the OS, although, like you, Dave, I don't think such drastic measures would be required. (d) There's still the lurking Mac OS X 10.4.x dual-processor bug that causes panics. See the discussion in the macos-x-server archives and the fact that someone on the list found and fixed the bug and has re-compiled that section of the Darwin kernel and has submitted the fix back to Apple, but it didn't make it into 10.4.3. Perhaps 10.4.4. This is actually what caused us to get the single-processor Xserve version because our present load is low and we valued reliability, and we will evaluate later in this year the choice between upgrading our Xserve G5 to a DP vs. waiting and replacing it with the Intel version Xserve when that arrives. But, until this dual processor bug is fixed in Apple's standard release, I'm hesitant to have a DP configuration. (e) My big uncertainty comes from my lack of knowledge of the Mach kernel internals, in that I'm not sure how faults are handled between the dual processors. I did a Unix port 20 years ago (4.2BSD), and did also some multiprocessor kernel work back then on Motorola processors, and one of the concerns we found was if different mask revisions of processors were used in the same multiprocessor setup, different mask revs could push different microstate information for some types of faults - it didn't happen on clean stuff like syscalls or traps or interrupts, but bus faults, page faults, etc., could, in some circumstances, push different internal state information, which either required that the return from the fault occur on the same processor that fielded the fault originally (so that the microstate pop would work), or else that we require that all processors in the system be of the same mask rev level so that any processor could do a microstate pop of information pushed by any other processor. Because I haven't studied the lowest level code of the Mach kernel, I don't know how this is handled in Mac OS X, or if it is a non-issue, but I do understand that Mach is symmetric rather than asymmetric in design. It seems that this might not be an issue because the processor modules are available as user-replaceable spare parts (see item (4), above). The issue of serial number / model number not matching the configuration is less of a concern to me - heck, our BTO Xserve was invoiced and had a packing list that matched what we ordered, but the configuration of the server in the box didn't match the packing list or invoice (had the wrong size disk drives - we ordered 250 GB, it had 80 GB). Suffice it to say that much correspondence with Apple has happened over that, and Apple replaced the 80 GB drive as "defective" - wouldn't store 250 GB - under our support contract. Sigh. But our configuration at Apple still (incorrectly) says the server has 80 GB drives, even though the invoice says different. Go figure. I suspect that the 2.0 GHz SP Xserve G5 is getting near end-of-life, so I don't know how much longer the 2.0 GHz processor modules will be readily available. But at some point, probably about a year from now, 2.0 GHz Xserves will start being replaced and they will become attractive as spare parts donors. So, that's my analysis. Looks to me like it really might work. The risk seems to be, at worst, the $687.50 for a second 2.0 GHz Xserve processor module, don't know what The Mac Support Store's restocking fee would be if it didn't work. The Mac Support Store is an Apple Authorized Reseller and repair depot, I'd suggest that Buckie Joe (?) give them a call to discuss. To paraphrase Josh Wisenbaker's motto, "Breaking your server to save mine." Regards, Russ !DSPAM:43be183a755721468083054! |
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