There was an embarassingly bad TCP window size scaling bug in RHEL 5.4. It wasn't acknowledged in any way by RedHat, until late in 5.5, and wasn't fixed until 5.6.
I faced long and continued skepticism from the network people, and the Linux admins, that such a bug could exist in a RHEL release, that I would be able to discern such a bug, or that it wasn't a TSM problem. (It took about six months to resolve that particular problem, and would've taken even longer if we'd have started looking at it sooner.) Only a small percentage of Linux boxes get their network cards barraged with heavy-heavy receive traffic all night every night. So bugs like that don't get discovered quickly, or fixed quickly, or documented quickly. (This one affected other brands of backup software too.) Also, there is at least one brand of inexpensive 10GBE cards that are complete garbage. They overheat under heavy use, and typically cause the whole system to crash. (For political reasons, we abandoned 10GBE on the backup servers.) These cards are sold under three or four different brand names, and were the ones sold by the the top 3 big Intel box makers, because they are the cheapest cards available. I'll stop here, before I get into editorializing. [RC] shawn.d...@americas.bnpparibas.com Sent by: ADSM-L@VM.MARIST.EDU 04/20/2012 09:38 AM Please respond to ADSM-L@VM.MARIST.EDU To ADSM-L@VM.MARIST.EDU cc Subject [ADSM-L] AIX vs Linux 2012 I know this has been discussed in various forms over the years, but I'm specifically wondering about the current state of hardware I have a long history with TSM on AIX. It's stable, familiar and an I/O powerhouse. Our Unix admins also favor AIX for serious, heavy-duty workloads. We are looking at refreshing our largest P570 now. I discussed this with our unix admin, who also has a very high opinion of IBM. He said that current SandyBridge implementations can really make Linux a contender in terms of I/O and CPU performance. And at about 1/7th the cost. I normally dismiss Linux because I was under the impression that you would need many inexpensive servers to equal one P-series for I/O. It wouldn't be worth it with the added management of dealing with multiple TSM Servers. Now with DB2, TSM seems to be going more towards the monolithic direction if anything. But If I can get a single 32-core, 128GB ram intel server that can actually push multiple 10gbe and 8gb FC interfaces I am finding Linux a little more attractive. Does anyone have any stories, gotchas, or opinions with replacing a P-series host with a modern Intel system 1 for 1? Regards, Shawn ________________________________________________ Shawn Drew This message and any attachments (the "message") is intended solely for the addressees and is confidential. If you receive this message in error, please delete it and immediately notify the sender. Any use not in accord with its purpose, any dissemination or disclosure, either whole or partial, is prohibited except formal approval. The internet can not guarantee the integrity of this message. BNP PARIBAS (and its subsidiaries) shall (will) not therefore be liable for the message if modified. Please note that certain functions and services for BNP Paribas may be performed by BNP Paribas RCC, Inc. If you are not the intended addressee, please inform us immediately that you have received this e-mail in error, and delete it. We thank you for your cooperation.
