Steve Modica
Forum Replies Created
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Running gross tests like disk benchmarks only tells you a little about the problem.
Ideally, you’d have something that let you look at individual IOs so you could see their latency and size.
For example, perhaps in the new OS, you aren’t getting the same IO size as before. That might be a simple tuning issue. Perhaps you are running out of a disk IO resource after a short period (you would see the IOs stay fast and large, but perhaps stop coming as rapidly since they are queuing up for buffers to allocate).On Mac OS X, there’s dtrace, so you can gather a lot of information like this. I’m not a windows guy.
Steve
Steve Modica
CTO, Small Tree Communications -
[Jon Schilling] “The SAS drives are going to give you the better performance.”
This isn’t really true. The underlying spindle isn’t any faster and the vendor themselves will tell you the SAS front in (dual ported) is really for redundancy.
That being said, I think there might be a slight increase in performance if you had a dual ported SAS backplane and two channels driving it. Theoretically, you could see some better pipelining.
(We’ve tested this BTW. The drives perform the same in a non-dual ported environment. There is no latency improvement)
Steve Modica
CTO, Small Tree Communications -
A hang like that is almost certainly the fault of the high point driver. Regardless of your raid configuration, the machine should not hang. That’s a bug.
Steve Modica
CTO, Small Tree Communications -
We tried to quantify the need for jumbo frames. We did a lot of testing and found that imacs without jumbos were more susceptible to drops and such. For example, an imac would drop when hitting a PS file on the timeline or anytime there was a trasncode required (filters, mixed formats etc). It was more fragile than a mac pro with jumbo frames.
We haven’t gone back and worked on this more since FCPX came out and they added jumbos back to imacs.Steve Modica
CTO, Small Tree Communications -
The new iMacs support jumbo frames. There was only one generation that didn’t.
From the exchanged emails, I think the apple guys thought that segmentation offload was equivalent to jumbos. The idea is the OS hands the card large chunks and the card handles chopping them up and putting headers on them. To the OS, this delivers similar benefits.
The problem is that there’s nothing like this on the receive side. So your poor imac must deal with tons of 1500 byte frames to play your video.
10Gb does have offloads like this (Receive Side Coalescing). We fully support this. So moving into 10Gb, jumbo frames may not matter so much (the irony being that 10Gb cards support jumbo frames anyhow).Steve Modica
CTO, Small Tree Communications -
Download Small Tree stream counter app (https://www.small-tree.com/downloads_a/123.htm) and run it one or more of your clients to the storage and see how it does. We’ll show you all the IO and the latency and you’ll see if a bunch of them are falling out of the window.
The app currently emulates FCP 7, but we’ll be adding FCPX emulation soon.
Steve
Steve Modica
CTO, Small Tree Communications -
Probably the com.apple.FinderInfo extended attribute is dorked. You can use xattr to look at a good one and strip off the bad and replace.
Steve Modica
CTO, Small Tree Communications -
They will be very shortly. We haven’t checked in the changes yet (we’ve been working on some other gigabit chips). Magma won’t list them until they have them in house and have tested themselves.
Steve Modica
CTO, Small Tree Communications -
You could get a Magma three slot box and a Small Tree 6 port NIC and have a couple slots left over for something else.
The benefit of the magma is that they use a high end PCIE 3 switch in the box which gives them an advantage over PCIE 2 daisy chaining (like you’d do with multiple 1 slot boxes).
I’m not sure what you mean by option 1. There are no thunderbolt ethernet hubs. That would be the ame as putting a 6 port card in there.
Steve
Steve Modica
CTO, Small Tree Communications -
[Dave Malone] “How long was “for a while”?”
Til golden brown and delicious
Steve Modica
CTO, Small Tree Communications