On 04/08/2011 07:22 PM, J.P. King wrote:
>
>> No, I haven't tried a S7000, but I've tried other kinds of network
>> storage and from a design perspective, for my applications, it doesn't
>> even make a single bit of sense. I'm talking about high-volume real-time
>> video streaming, where you stream 500-1000 (x 8Mbit/s) live streams from
>> a machine over UDP. Having to go over the network to fetch the data from
>> a different machine is kind of like building a proxy which doesn't
>> really do anything - if the data is available from a different machine
>> over the network, then why the heck should I just put another machine in
>> the processing path? For my applications, I need a machine with as few
>> processing components between the disks and network as possible, to
>> maximize throughput, maximize IOPS and minimize latency and jitter.
>
> I can't speak for this particular situation or solution, but I think in
> principle you are wrong. Networks are fast. Hard drives are slow. Put
> a 10G connection between your storage and your front ends and you'll
> have the bandwidth[1]. Actually if you really were hitting 1000x8Mbits
> I'd put 2, but that is just a question of scale. In a different
> situation I have boxes which peak at around 7 Gb/s down a 10G link (in
> reality I don't need that much because it is all about the IOPS for
> me). That is with just twelve 15k disks. Your situation appears to be
> pretty ideal for storage hardware, so perfectly achievable from an
> appliance.
I envision this kind of scenario (using my fancy ASCII art skills :-)):
|| ========= streaming server ======== ||
+-----+ SAS +-----+ PCI-e +-----+ Ethernet +--------+
|DISKS| ===> | RAM | ====> | NIC | =======> | client |
+-----+ +-----+ +-----+ +--------+
And you are advocating for this kind of scenario:
|| ==== network storage ===== ||
+-----+ SAS +-----+ PCI-e +-----+ Ethernet
|DISKS| ===> | RAM | ====> | NIC | ======== ...
+-----+ +-----+ +-----+
|| ===== streaming server ====== ||
+-----+ PCI-e +-----+ PCI-e +-----+ Ethernet +--------+
... ==> | NIC | ====> | RAM | ====> | NIC | =======> | client |
+-----+ +-----+ +-----+ +--------+
I'm not constrained on CPU (so hooking up multiple streaming servers to
one backend storage doesn't really make sense).
So what exactly what does this scenario add to my needs (besides needing
extra hardware in both the storage and server (10G NICs, cabling,
modules, etc.)? I'm not saying no, I'd love to improve the throughput,
IOPS and latency characteristics of my systems.
> I can't speak for the S7000 range. I ignored that entire product line
> because when I asked about it the markup was insane compared to just
> buying X4500/X4540s. The price for Oracle kit isn't remotely tenable, so
> the death of the X45xx range is a moot point for me anyway, since I
> couldn't afford it.
>
> [1] Just in case, you also shouldn't be adding any particularly
> significant latency either. Jitter, maybe, depending on the specifics
> of the streams involved.
>
>> Saso
>
> Julian
> --
> Julian King
> Computer Officer, University of Cambridge, Unix Support
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--
Saso
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