[mythtv-users] Hardware Setup Advice

Simon Hobson linux at thehobsons.co.uk
Wed May 23 14:25:59 UTC 2012

I wrote:

>Your biggest issue will be disk seek times. Essentially, if you are 
>recording 18 streams, then you have 18 threads which are syncing a 
>file to disk once a second. This means the disk will be trying to do 
>18 seeks & writes/second - and a cursory look at the specs of most 
>disks will reveal that this is likely to lead to a bottleneck.

Correction, that should be "at least" 36 seek & writes/second.
Each file write will be accompanied by at least one update to 
filesystem metadata, and quite likely more than one.
As a minimum, the file length will need updating. Quite frequently, 
some free space will need adding to the file - so the free space 
map/tree checking for some space, and updating to mark it as used, 
and then the file data updating to add the new bit of space.

Simon Hobson

Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
author Gladys Hobson. Novels - poetry - short stories - ideal as
Christmas stocking fillers. Some available as e-books.

More information about the mythtv-users mailing list