Re: Any FSFS rep-sharing experts out there?

On Mon, Oct 5, 2009 at 9:52 AM, Branko Čibej <brane_at_xbc.nu> wrote:
> Daniel Shahaf wrote:
>> Branko Cibej wrote on Mon, 5 Oct 2009 at 18:08 +0200:
>>
>>> David Glasser wrote:
>>>
>>>> Is the ASF getting a measurable benefit from using rep caching?
>>>>
>>>>
>>> They have a half-gig rep-cache.db, so I expect yes.
>>>
>>
>> IIUC, the size of the DB is proportional to the number of (unique)
>> representations.  This doesn't tell anything about the amount of space
>> saved (by reusing representations).
>>
>
> Oh, yes, you're right. Silly me.
>
> But anyway the question is irrelevant. If we manage to lock up the
> server for tens of seconds because of a slightly larger-than-usual
> commit, we need to fix it. This is pretty much on my plate right now,
> but I'll ask around for help on understanding FSFS details.

The relevance of the question is that if you're not actually getting a
benefit from rep caching (a feature whose cost/benefit ratios I
personally felt were not strong enough to warrant it being turned on
by default), you could just avoid all the contention by not using it.

--dave

-- 
glasser_at_davidglasser.net | langtonlabs.org | flickr.com/photos/glasser/
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