HDD util is 100% - aio questions

[Cristian Rusu]

Hello

Well, we don't have a single box, we have a few setups with large slow HDDs
and a couple of edge servers running on 1.5TB RAID SSD for actual streaming.

Right now it's stable(70% max util) as we managed to write a caching code
so basically the slow HDDs mainly feed the edges and only a few users at
first.

The edge servers are way faster and cope with 10Gbit bandwidth so far.

I just hoped that aio is a solution for less strain in HDDs util%.

As for page cache, that is pretty useless as web-mysql boxes does just fine
in serving up to 2500 connections per second.

The main issue is around getting large videos in and out of HDDs fast.

---------------------------------------------------------------
Cristian Rusu
Web Developement & Electronic Publishing

======
Crilance.com
Crilance.blogspot.com


On Mon, Feb 4, 2013 at 8:29 PM, Lukas Tribus <luky-37 at hotmail.com> wrote:

>
> Yes, I'm aware, thats why I told him to monitor the box carefully.
> However, async IO is not so easy to accomplish under linux, and since he is
> also using the streaming module, things can get complicated.
>
> I wonder if switching to FreeBSD would be a better idea to avoid the linux
> AIO limitations (as in the nginx documentation).
>
> Anyway, he needs to do some serious testing/thinking/spending time with
> it. Nobody will come up with the perfect configuration for him resolving
> all the issues.
>
>
>
> ----------------------------------------
> > Date: Mon, 4 Feb 2013 19:19:09 +0100
> > From: jgehrcke at googlemail.com
> > To: nginx at nginx.org
> > Subject: Re: HDD util is 100% - aio questions
> >
> > 64 GB of RAM might not be sufficient for keeping a significant part of
> > his video data in memory. Hence, depending on the number of concurrent
> > users and the average size of the videos Cristian wants to stream it is
> > entirely possible that caching videos in memory does not help at all. In
> > this case, he needs proper disk I/O settings.
>
>
> _______________________________________________
> nginx mailing list
> nginx at nginx.org
> http://mailman.nginx.org/mailman/listinfo/nginx
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.nginx.org/pipermail/nginx/attachments/20130205/57f2110f/attachment.html>