Re: [9fans] Fossil+Venti system memory requirements to be aware of?

[Steven Stallion <sstallion@gmail.com>]

Hi Jim,

It's important to point out that the arena size does not have to match
the size of an arenas file. In my case, I do something similar where I
use 2GB for an arena but keep my arenas files at 2GB (I don't have
much use for keeping multiple arena files).

More indexes help to an extent. My fs isn't under exceptionally heavy
load, but I've found that 2 seem to work out nicely for my
configuration.

Steve

On Wed, Nov 2, 2016 at 1:44 PM, James A. Robinson <jimr@highwire.org> wrote:
> On Wed, Oct 19, 2016 at 9:47 AM Steven Stallion <sstallion@gmail.com> wrote:
>> In short, start small and grow as needed. For reference, when I ran
>> Coraid's fs based on 64-bit Ken's (WORM only, no dedupe) in RWC
>> (based on the main fs in Athens). Over the course of a few years
>> the entire WORM grew to around 35GB. This was for a couple dozen
>> people working full time. I believe I had the LUN configured to
>> something rather large at the time - around 12TB. All wasted space.
>
> Hi,
>
> So if you were setting up a new filesystem for the same group, and
> were using venti, would you be using the default 500 mb arena size
> (meaning 70+ arenas), or would you be sizing them at a larger size,
> like 1 gb, 2 gb, etc?
>
> The "setting up venti" page indicates that multiple small disks
> help with performance on venti due to using more indexes, but I
> can't tell if that translates to more partitions (e.g., 1 RAID 1+0
> disk split into multiple smaller partitions, and divvied up into
> isectX and arenaX drives).  I guess it probably comes down to
> how well (or poorly) the underlying disk array performs at random
> read/write ops.
>
> I see that AWS S3 allows for up to 5 gb in a single PUT, or 5 tb
> using multipart streams, and am thinking that using 1 to 5 gb
> arenas might make sense as a more modern "sized for for easy
> offline backup" default.
>
> Jim
>