[mythtv-users] mythtv-users Digest, Vol 56, Issue 71
Kevin Nelson
kevin at soundcyst.com
Fri Nov 16 12:24:39 UTC 2007
On Nov 15, 2007, at 8:19 PM, mythtv-users-request at mythtv.org wrote:
> Chris Ribe wrote:
>> On Nov 15, 2007 9:50 AM, Mark J. Small <msmall at eastlink.ca> wrote:
>>
>>> On November 15, 2007, Tom Dexter wrote:
>>>> On Nov 15, 2007 5:39 AM, Mark Small <msmall at eastlink.ca> wrote:
>>>>> In such a system, your biggest bottleneck will likely be
>>>>> bandwidth to
>>> the
>>>>> hard disk(s). If you've got 4 folks watching HDTV streams,
>>>>> that's a
>>> TON
>>>>> of data the gets written and read constantly.
>>
>> While I won't argue that I/O is a potential issue, it not THAT big
>> of an
>> issue. 4 HD streams only amount to about 7MB/s of data. If you
>> have 4 HD
>> tuners, you'll probably want more than one disk for storage, but
>> you could
>> get by with a single SATA disk.
>>
>> -chris
>>
>
> I don't know where everyone got this number of 4 streams. The OP said
> he was going to have 8 clients and 4 tuners. That give a possible
> maximum of 12 streams of data (+ 4 depending on how he sets up
> commercial flagging). Disk I/O will be his major concern. And it's
> not
> total sustained throughput that will be the issue, it'll be all the
> constant seeking that will be the issue...
>
> - Wade
Hi everybody, thanks for all of the responses.
It's clear to me now that I should have mentioned that I am looking
at the ASUS P5E motherboard with as many SATA hard drives as i can
fit into the case.
The mobo only supports 6 SATA connections, so i'm guessing that I can
only have 6 drives in a RAID configuration via the mobo's native RAID
hardware. Since I am planning on using a Chenbro 3U chassis that has
8 drive bays, I would like to be able to support up to 8 drives in
RAID, so an external card might be necessary.
My conclusion based on your input is that with this many drives (and
the seek time distributed appropriately, a Core2 processor will be
powerful enough to accomplish the task at hand.
Of course, recommendations on a RAID controller or a mobo that
supports 8 SATA drives and is linux / core2 compatible would also be
appreciated,
To clarify -- Wade is correct in assuming that the server will be
dealing with a maximum of 12 streams rather than 4 or 8. Each TV
might be viewing some recorded program (8 streams) while 4 separate
live broadcasts are being recorded. This is a circumstance that the
server must be able to accommodate frequently and efficiently.
(honestly, i'm not sure if my client will frequently use that much
power often, but i am certain he'll push it to that limit at least
once).
Thanks again, as you all have been profoundly helpful.
-kevin
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