Re: sharing DL_DIR?

[Rich Pixley <rich.pixley@palm.com>]

Excellent, thanks.  That's the news I was hoping for.

--rich

On 2/22/12 15:41 , Saul Wold wrote:
> On 02/22/2012 03:33 PM, Rich Pixley wrote:
>> Is it reasonable to expect to share DL_DIR between multiple builds?
>>
> Absolutely, We share DL_DIR via NFS across multiple machines and builds.
>
>> That is, are downloads properly locked so that multiple concurrent
>> downloads of the same file won't collide? And if so, are they NFS safe
>> locks?
>>
> Yes, as far as I know.
>
>> Or must each build download it's own copies of every component?
>>
> No need.
>
>> I ask because our, (Palm), branch has been, but it's a bit of a nuisance
>> to pick a suitable locking mechanism that is both functional and performant.
>>
>>    * Flock/lockf aren't reliably supported in heterogeneous environments.
>>    * The old lockfiles don't work over NFS. Lock directories apparently
>>      do, but trying to clean these up after interruptions or failures is
>>      a losing battle so if we do use these, we end up with orphan locks
>>      periodically.
>>    * With NFS as a possibility, we can't assume any kernel local IPC
>>      mechanism, so sysV ipc is out.
>>    * It seems like a pretty huge overhead to try to create any sort of
>>      zeroconf overhead.
>>
>> Our solution so far has been to use NFS lock directories for multiple
>> machine builds and flock/lockf for single machine builds. This mostly
>> works, though it's not ideal, and it's significantly faster than
>> downloading/copying all of the component source multiple times even over
>> local mirrors.
>>
> I think we are using a very basic locking mechism that creates the
> lockfile and a donefile when complete.  It seems to work well enough.
>
> Sau!
>
>> --rich
>>
>>
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