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Re: fsync()-in webdav PUT

Nagy, Attila
March 02, 2018 03:52AM
On 02/28/2018 11:04 AM, Aziz Rozyev wrote:
> While it’s not clear why one may need to flush the data on each http operation,
> I can imagine to what performance degradation that may lead of.
I store data on HTTP servers in a distributed manner and have a catalog
of where each file is. If I get back a successful HTTP response for a
PUT operation, I want it to be true, so the file must be on stable storage.
If I just write it to a buffer and something happens with the machine
while the data is still in the buffer, I can't trust that response and I
have to make sure the file is there in its entirety from time to time,
which is much much much much more of a performance degradation.
With clever file systems and/or good hardware (battery backed write
cache) it won't cost you much.
Anyways, it's completely irrelevant how fast you can write to RAM. The
task here is to write reliably. And you can make it fast if you want
with software and hardware.

>
> if it’s not a some kind of funny clustering among nodes, I wouldn't care much
> where actual data is, RAM still should be much faster, than disk I/O.
>
Let's turn the question this way: if you write to RAM, you can't make
sure that the file really made it's way to the storage.
Why do you upload files to an HTTP server if you don't care whether they
are there or not?
You could use /dev/null too. It's even more faster...
Or just make your upload_file() function to a dummy "return immediately"
call.
That's even more faster. :)

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Subject Author Posted

fsync()-in webdav PUT

Nagy, Attila February 27, 2018 05:24AM

Re: fsync()-in webdav PUT

Maxim Dounin February 27, 2018 08:26AM

Re: fsync()-in webdav PUT

Nagy, Attila February 28, 2018 04:32AM

Re: fsync()-in webdav PUT

Aziz Rozyev February 28, 2018 05:06AM

Re: fsync()-in webdav PUT

Valery Kholodkov February 28, 2018 01:26PM

Re: fsync()-in webdav PUT

Aziz Rozyev February 28, 2018 04:44PM

Re: fsync()-in webdav PUT

Aziz Rozyev February 28, 2018 05:08PM

Re: fsync()-in webdav PUT

pbooth February 28, 2018 05:36PM

Re: fsync()-in webdav PUT

Valery Kholodkov March 01, 2018 07:26AM

Re: fsync()-in webdav PUT

Valery Kholodkov March 01, 2018 07:30AM

Re: fsync()-in webdav PUT

Nagy, Attila March 02, 2018 04:02AM

Re: fsync()-in webdav PUT

Nagy, Attila March 02, 2018 05:04AM

Re: fsync()-in webdav PUT

Nagy, Attila March 02, 2018 03:52AM

Re: fsync()-in webdav PUT

Maxim Dounin February 28, 2018 09:10AM

Re: fsync()-in webdav PUT

Valery Kholodkov February 28, 2018 01:56PM

Re: fsync()-in webdav PUT

itpp2012 February 28, 2018 03:28PM

Re: fsync()-in webdav PUT

Nagy, Attila March 02, 2018 04:14AM

Re: fsync()-in webdav PUT

Aziz Rozyev March 02, 2018 05:44AM

Re: fsync()-in webdav PUT

Nagy, Attila March 02, 2018 06:32AM

RE: fsync()-in webdav PUT

Reinis Rozitis March 04, 2018 07:42AM

Re: fsync()-in webdav PUT

Nagy, Attila March 05, 2018 05:32AM

RE: fsync()-in webdav PUT

Reinis Rozitis March 05, 2018 06:56AM

Re: fsync()-in webdav PUT

Valery Kholodkov March 05, 2018 08:14AM

Re: fsync()-in webdav PUT

Nagy, Attila March 05, 2018 08:56AM

Re: fsync()-in webdav PUT

Richard Demeny March 05, 2018 09:06AM

Re: fsync()-in webdav PUT

Maxim Dounin March 02, 2018 11:08AM

Re: fsync()-in webdav PUT

Valery Kholodkov March 02, 2018 02:50PM

Re: fsync()-in webdav PUT

Maxim Dounin March 02, 2018 07:44PM



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