[mythtv-users] Low Power System

[James Linder]

On 8/3/17 8:00 pm, mythtv-users-request at mythtv.org wrote:
> [snip]
>>> if you use flash then 2 stuff:
>>>      partition your flash such that (say) 20% is unpartitioned. That
>>> gives a stock of sectors that trim can claim as sectors get worn out
>>>      deal with mysql logging. The log will wear out your flash in a year.
>>>      I run trim as a daily cron task. Recomendation is to not put it in
>>> fstab.
>>>      BTW a 2.5" 1T spinning disc adds little to power, but makes life
>>> much easier
>>>
>>> James
>> Thanks James, I actually do most of that now, with the exception that trim
>> is in fstab - any sources on why not?
>>
> If you're going to leave 20% of your drive un-partitioned you probably
> don't need to worry too much about TRIM. You're always going to have
> 20% spare sectors to swap things into.
>
> It's certainly much less important that sorting out unnecessary logging.
I seek words of wisdom:

If you *do not* leave some un partitioned, space implication is that the 
file system will mark and not use sectors as they get used-up.
What happens when you delete a file whose inode is used-up. As I 
understand the 1 indirect inode is fixed in place the 2 and 3 indirect 
inodes could be relocated
[pointer to a sector of inodes, pointer to a sector of pointers to inodes].

Can someone who understands the gritty detail please comment

Thanks
James

PS I think that one would never use-up flash, recording or deleting 
files but mysql logs will (and do) use up the flash in a year. I also 
think that short term storage ie a day, a week or a month of recordings 
is easily do-able on flash, but long term storage should be spinning
ie a 256G or even 500G flash is quite doable, but 2T or 4T is rather 
pricey still.