Steve Modica
Forum Replies Created
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We’ve been testing ST RAID II (6Gb) with 10Gb and it’s very fast. We’re using 3Gb SATA drives on 6Gb SAS ports. There’s a nifty feature that lets 6Gb SATA multiplex 2 3Gb drives.
The results are very good. We can sustain about 350MB/sec for each client out to about 4 clients (depending on the codec) off a single chassis.
I would like to stress that this type of load requires a lot of fairly aggressive tuning. The OS does not have enough of anything laying around by default.
Steve Modica
CTO, Small Tree Communications -
That’s some really interesting output.
I’m not 100% sure how apple decides to turn something red. I think it means it’s not responding to interrupts.
The CPU time is all system time, which indicates it’s the kernel or system calls doing stuff.
What’s really interesting is all that “active” memory. That’s very unusual. Again, I can’t be sure what things apple chooses to put in that bucket, but I’m guessing it’s dirty cache data that has not flushed to disk. I would be interested to see what happened if you killed AE and let it sit. Does all that eventually turn blue (inactive?)
It’s almost like the IO is stopped and so it’s all just going into cache and sitting thereSteve Modica
CTO, Small Tree Communications -
Perhaps a better analogy:
You want to haul your 28′ boat with your VW. So you hook it up and discover that you can’t move it unless you put the car in first gear. So you start driving that way. You would clearly realize that you were over-revving the engine and stop. You might imagine the transmission was having trouble.
Computers don’t limit themselves. So they’ll use up all the memory, pile up the IO queue, max out the CPU etc. All these things are fine for those moments when some intense thing is running. However if you are a production guy (for example, running weather simulations), you don’t want to run like that. It’s not efficient and it tends to have problems during your 3 week simulation run.Steve Modica
CTO, Small Tree Communications -
If I personally were buying a system and the idea was “the fastest thing I could get for the money”, I’d go with a 5500 chipset and the Westmere (5600) processor. You get three memory channels instead of 2 and more cores. Assuming you’re running Windows, you will get a lot of the parallelims benefits they put in. Blue Screens can appear twice as fast!
Just make sure to populate the memory in banks of 3, not 4. Or the system will drop down to 2 memory channels. So you want 12, 24, 48 etc.
That’s a server chip and it’s in the mac pros. (I think you get more PCIE channels in that too)
Steve Modica
CTO, Small Tree Communications -
You should look at what’s happening on the system during the run. iopending, activity monitor, and things like that. Memory, cpu and storage throughput are all interesting.
What usually happens is that things work great under “normal” loads, but when you really stress something (like using up all the memory), the system has to start paging, it slows way way down, and then all these interesting timing windows open up for bugs to appear. So you don’t want to run “production” runs on a system that’s not running in the sweet spot. Apple (and most vendors I’m sure) don’t go around regression testing in resource constrained circumstances. (they may do this to test specific elements like the paging code, but they aren’t running rendering tests like this)
Steve
Steve Modica
CTO, Small Tree Communications -
As long as you have PCIE slots.
Storage is a huge bottleneck on all this stuff and if you need many Terabytes, you’ll need some sort of RAID card. SSD’s are very fast, but *good* SSDs are going in the 10-40K per TB range right now. You’ll need a lot of spinning disks to do many TB in realtime. (8 or so)
Steve Modica
CTO, Small Tree Communications -
If you want to go with 10Gb Ethernet and consider being future proof (like having Fibre Channel over Ethernet support for those 10Gb cards) you should buy from Small Tree.
If you poke around you’ll see Bob’s post about HP switches and flow control/jumbo frame issues. We write the drivers for the mac, and we’ve literally had every line of switches in the lab at one point or another for testing. We sell stuff that works. Most vendors have no idea flow control even exists, much less know how to support it.
As for storage, we’ve written AoE (coraid), iSCSI and FCoE drivers for Mac as well as an entire FCoE target stack for linux (in house). We can pretty much debug anything from a disk problem out through a kernel bug.A file based network storage setup is definitely the way to go. It’s simpler, scales better, and is easier to manage. If you do it with us, you’ll use a mac pro as a server and you can repurpose that later onto someone’s desk if you upgrade the server.
Steve Modica
CTO, Small Tree Communications -
One of our guys was a windows guy for a long time. He eventually made the leap to OS X completely and used OS X apps.
iCal, Address Book and Apple Mail integrate very nicely and sync with my phone (and will also sync with google).
If you really want to, you can go get MS Office 2011 and have the stuff you have now, but you can also use the built in tools and be very happy. You can automagically add things to your calendar and acknowledge meetings and add new contacts to address book. You can do it all from within Mail.Steve
Steve Modica
CTO, Small Tree Communications -
Sounds like spotlight indexing to me. Run “top” in a terminal while that’s happening. See what’s running
Steve Modica
CTO, Small Tree Communications -
[Eric Jurgenson] “Anybody think this is going to blow the doors off of 10G Ethernet? Product should be appearing in the next few months, and sounds like the first implementation will be copper, 10G, with relatively short cable runs. Seems like it will support daisy chain as well as switched networks. Pricing should be a small fraction of 10G Ethernet, and should enable enough bandwidth to the client to support uncompressed HD and digital cinema formats.”
I think it’ll be more like firewire in terms of the Niche it fills. I imagine it will be a better storage medium than 10Gb for local attach, but we’ll have to see if it can stand up to 100Gb. Are you ready for that? Specs done, hardware is coming.
Steve Modica
CTO, Small Tree Communications