Bug#776485: systemd: Enable readahead by default

[Michael Biebl]

Am 30.01.2015 um 03:41 schrieb Ivan Baldo:
> 
> El 28/01/15 a las 13:36, Michael Biebl escibió:

>> As for the version in expiremental: Upstream dropped the readahead
>> functionality in v217, so there is nothing to enable anymore:
>>
>>>          * systemd's readahead implementation has been removed. In many
>>>            circumstances it didn't give expected benefits even for
>>>            rotational disk drives and was becoming less relevant in the
>>>            age of SSDs. As none of the developers has been using
>>>            rotating media anymore, and nobody stepped up to actively
>>>            maintain this component of systemd it has now been removed.
>     In my machine it saves 20s (desktop), I am surprised that they say
> it doesn't give benefits for rotational disks.
>     If you have a rotational disk give it a try, remember you need to
> boot twice to see the benefit.
>     It is the best implementation of read ahead that I have seen so far,
> sad to see it disappear, I hope that solid state disks become bigger and
> cheaper in about two years to justify buying them myself (many in
> undeveloped countries face the same situation, too expensive to us yet).

Unfortunately, there is not much we can do downstream. At least I
wouldn't want to re-surrect the code and ship it as a downstream patch.
That would be quite unmaintainable.
Myself, I'm using a SSD, so personally I never bothered to enable readahead.
The best chances to have is probably raising this issue on the upstream
mailing list. Although I would not be too optimistic.


>> I'm tagging the bug wontfix for now, but I'm inclined to just close,
>> since going forward, it probably doesn't make sense to keep it open.
>     Should be closed yes.
>     Maybe you would like to add the command to the README.Debian in
> Jessie for the people that wants to try it and of course warn that it
> was removed in v217, to make it a bit more visible.

We were actually considering to already disable readahead for jessie, so
people don't get used to it and are then disappointed in jessie+1.

It's probably a bit late to do that now, but adding a note to
README.Debian that readahead is going away in jessie, might be compromise.




-- 
Why is it that all of the instruments seeking intelligent life in the
universe are pointed away from Earth?

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