[mythtv-users] Building a new MythTV Backend for 2022

[Mike Perkins]

On 10/01/2022 16:00, Alain wrote:
> On 10.01.22 11:06, Mike Perkins wrote:
>> On 10/01/2022 08:46, Stephen Worthington wrote:
>>>
>>> If you want to record to the SSD, then you are likely to hit the
>>> lifetime write limit fairly rapidly.  But just running MythTV and
>>> normal Linux on an SSD and there are no problems with lifetime. You
>>> still need to worry about it just dying unexpectedly, like any disk
>>> drive (or any electronics, for that matter).
>>>
>> I would think that is the other way around. Sure you are writing TB chunks to a recording disk but 
>> it is written once and then read for a while until deleted. On the other hand that database is 
>> getting *hammered* all the time as it updates e.g. seek tables. And do not forget the daily 
>> mythfilldatabase updates! Lots and lots of small updates to files and inodes all over the place.
>>
>> The one thing that you can be certain of with any (currently manufactured) SSD is that it is 
>> guaranteed to fail. Once it reaches the lifetime limit then bang! it's gone. On the other hand, a 
>> looked after HDD will just keep spinning.
>>
>> Processor speed and memory increases are such that I don't need that extra disk write speed, not 
>> for something as non-critical as mythtv. SSDs undoubtedly have a place for certain use cases but 
>> thrashing a media database isn't it, in my view.
>>
>   My personal experience is that both SSD and disk will fail after a few years. I got lucky, my last 
> failure for an 8TB disk was just inside the 2 years warranty provided by the store. Not so lucky 
> with the SSD failure which occurred two months before.
> 
>    While it is true that the DB on SSD will write more often, there is the advantage of being 
> faster. As as safety measure, I always either use mirrors (for SSD) or RAIDZ (ZFS) for the HD.
> 
Yep. But with an SSD the end is almost guaranteed while a HDD may go on for a random, and usually 
much longer, length of time. Nobody is counting the writes.

I have HDDs sitting in my box which are perfectly useable except for the fact that their interface 
is no longer supported.

The other major factor is that when an SSD fails, it's dead. When an HDD fails, you have an even 
chance of recovering all or most of the data before it goes completely.

-- 

Mike Perkins