I've been spending a bit of time in the lab exploring the options on the DL380. My main goal is to further reduce the power draw of the server and I'm happy to say I have an 8 core / 128GB config that idles at 80watts. It tops out around 200 watts. That means that this server runs less at maximum than a G6 with the same core count and memory would idle. This is Moore's Law in action. I'm not building special purpose servers like Facebook or Google which are great for what they are doing. This is just careful selection of components from what is available and keeping an eye on the cost metrics. A 100GB flash drive is roughly the same cost as a 450GB SAS drive. But it's 5watts less per drive. Also 16GB low voltage dimms are basically the same $/GB as 8GB dimms. Using 8 16GB dimms instead of 16 8GB dimms gives you great power savings. Probably the most significant change is that 8 cores used to require 2 processors. So choosing a single 8 core processor drops the power as well. If you are dealing with software licenses that charge by core, then this also helps keep cost flat, while per socket licenses would actually go down.
Probably the biggest change in this server generation is that the PCIe controller is now built on the chip. While this is overall a nice thing, it also is something to understand if you use lots of PCIe cards in your servers. The DL380 gen8 can have 6 PCIe slots, but that requires that both processor sockets be populated.
The onboard RAID also has had a major upgrade to be able to handle several SSD drives on the system. I've run 50,000 IOPS with one setup and never had issues. There are also some exciting things coming soon with a new firmware that HP previewed at HP Discover this year that makes this a very compelling hardware platform for big data (but that's another post). One other curious thing is that with raid5 on SSDs, we pretty much don't see a performance hit when running in raid5 (3+1) at least at the low end of processing. I can write 19,000 IOPS with a single thread. That number doesn't really scale with multiple threads. With mirroring, the limit was just over 6,000 IOPS so it looks like raid5 gives linear scalability. I have to dig into that more because something about goes against most everything I have learned in 20 years of system administration.
A few things have been painful. We've seen a return of firmware bugs and compatibility issues with 10gb that were cable length and 10gb switch firmware related. If you know what the picture below is from then you might have an idea of how painful it has been. I'm referring this to the Eye of Sauron in your 10Gbe network (and it's good when it's open). But all those issues are being worked out in the lab and it's looking great going forward.
My only gripes with the servers is that HP redesigned the rail kits and they are much harder to rack without help than they used to be and they moved the power button to a weird spot on the ear of the server. Other than those items, it's another solid product in the DL380 line.
No comments:
Post a Comment