[mythtv-users] ramfs for mysql

[Raymond Wagner]

On 1/5/2012 03:04, Simon Hobson wrote:
> While I understand your position, there are other pages that start
> with something along the lines of "this can break your system" and
> therefore could be considered unofficial hacks that are a really bad
> idea - but solve a problem for someone ? One of them has one of my
> database editing scripts (aka hacks) on it. Perhaps pages need to
> start being flagged to indicate whether they are officially
> sanctioned, or unofficial dirty hacks ?

Basically, there are three types of content on the wiki.  You have 
"officially sanctioned", or otherwise acceptable information.  You have 
dirty hacks that may go against the "manual database access is bad" 
rule, but generally aren't harming anything, and stick around until a 
better or more acceptable solution to perform the same task exists.  
Then you have bad information, that shouldn't exist at all, or should 
exist as a side note as "this is wrong" or "never do this".  Running 
MySQL in a tmpfs is of the last type.  It has been documented on the 
wiki several times in the past, and it has been rolled back or the page 
deleted each time.

> This user clearly does see a need for it, so the "unnecessary" part
> of your statement is not correct. True, it is dangerous, but as long
> as this is made perfectly clear, along with measures to mitigate that
> risk, then personally I think it is a valid topic.

The very first message in this thread mentioned trying to resolve the 
issue by using different filesystems for recordings.  The only reason 
this would have any effect would be if the database and recordings live 
on the same disk and partition.  We tell people not to do this for 
specifically this reason.

But I only have the one hard drive.  ----  So go buy another to put the 
OS and database on, or scrounge up an old spare drive from somewhere.

But I don't have slots on my board, or I don't have room in my case.  
----  So buy a better machine to run your backend on.  That's why we 
recommend running the master backend on a real PC rather than a tiny 
embedded machine.

I won't do it, I refuse.  ----  So turn off barriers, and continue 
operation as people did for years before switching to ext4 where 
barriers were enabled by default.  Live with the tiny risk that if you 
happen to be committing a transaction to disk the very instant the 
machine crashes, you end up with potential filesystem damage, and a 
database that needs repair.

There is no situation where stuffing a MySQL server into volatile 
storage is the best solution.