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<div class="moz-cite-prefix">On 8/11/2015 8:48 AM, Peter Bennett
(cats22) wrote:<br>
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<blockquote cite="mid:55CA1959.1000001@comcast.net" type="cite">
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Hi MythTV experts<br>
<br>
I am updating the wiki and wondering about the Balanced Disk I/O
setting.<br>
<br>
<a moz-do-not-send="true" class="moz-txt-link-freetext"
href="https://www.mythtv.org/wiki/Storage_Groups#Balanced_Disk_I.2FO">https://www.mythtv.org/wiki/Storage_Groups#Balanced_Disk_I.2FO</a><br>
<br>
The above page recommends if you are doing more than 2 recordings
at once to use this setting to get recordings put on separate file
systems to avoid buffer overruns. I am thinking of changing that
recommendation.<br>
<br>
A quick back of the envelope calculation tells me that I could
record some 50 HD programs at the same time on one disk drive,
based on 1 Gb/sec transfer rate and 8 GB per hour on each HD
recording.<br>
<br>
Clearly 50 at a time is theoretical and unlikely because it would
be affected by seek times. However HD programs vary from 3 GB to 8
GB per hour which means even more than 50 at the same time. Also
drives are rated at 6 Gb/sec which means 300 HD recordings at the
same time(!).<br>
<br>
You could surely record at least 10 HD programs at the same time
or maybe many more, so unless you have a very unusual situation it
seems that you need not concern yourself about hard disk
performance.<br>
<br>
I have 6 tuners and have never had a disk performance problem,
even while watching at the same time as recording, but I have
probably not recorded 6 channels at once.<br>
<br>
Does anybody have an opinion on this?<br>
<br>
Peter<br>
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</blockquote>
I have recorded 5 HD programs at the same time while watching
another with no problems (HD homerun). I only have a single
recording drive, but do have the DB on a separate drive. The
statement, "drives are rated at 6 Gb/sec", depends on the drive and
the system. SATA III drives are (when used with a SATA III
controller), but SATA II drives or IDE drives, or other drives are
not.<br>
<br>
Jay<br>
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