[9fans] Sensible fossil+venti partitioning

[9fans] Sensible fossil+venti partitioning

[csant]

After my first, fossil-only installation (following defaults), I am
thinking to set up a fossil+venti system on the same partition. What would
a sensible relationship of fossil vs. venti space be, i.e. how much space
makes sense to allocate for each? I am asking, since the installer does
not "suggest a sensible layout" as it already finds the previous
fossil-only installation and suggests that one instead... Not having ever
partitioned a fossil and venti machine, I am lost about what here might be
"sensible".

/c

Re: [9fans] Sensible fossil+venti partitioning

[Steve Simon]

Fossil needs to be big enough for all the changes you are likely
to do between venti snapshots.

Given venti usually snapshots every night I would say a fossil of
between 2 and 4 Gb is enough for most people.

You will want a swap of 1Gb or so, a 9fat of 100Mb, a sector
for nvram and perhaps another for fsconfig
(if you are mirroring or striping).

Give the remainder to Venti - about 5% to index and 95% to the arena.

These are my rules fo thumb, however others may disagree (ducks).

-Steve

Re: [9fans] Sensible fossil+venti partitioning

[csant]

> Fossil needs to be big enough for all the changes you are likely
> to do between venti snapshots.
Aha, so fossil itself is not going to store anything but the difference
 from the last venti snapshot?

> Given venti usually snapshots every night I would say a fossil of
> between 2 and 4 Gb is enough for most people.
>
> You will want a swap of 1Gb or so, a 9fat of 100Mb, a sector
> for nvram and perhaps another for fsconfig
> (if you are mirroring or striping).
>
> Give the remainder to Venti - about 5% to index and 95% to the arena.
I seem to understand that Plan 9 can only boot from a primary partition -
is there any problem having venti on a secondary partition?

How much hassle is it to mount venti on a different (secondary) partition?
In that case, how much trouble have I to go through to simply set up venti
on that partition and start using it, without having to re-install and
-format everything?

/c

Re: [9fans] Sensible fossil+venti partitioning

[Steve Simon]

> Aha, so fossil itself is not going to store anything but the difference
>  from the last venti snapshot?

Just to be clear, fossil stores the whole file if it differs from
venti not just a diff.

Venti however compresses data and factors out duplicate blocks
from all files so is very space efficent.

Fossil can also store its own snapshots but these are not compressed
and are usually reclaimed after a day or two. I use this to take a
fossil snapshot every 15 mins which is kept for 3 days and  venti snapshot
taken every night which is kept forever.

> How much hassle is it to mount venti on a different (secondary) partition?
> In that case, how much trouble have I to go through to simply set up venti
> on that partition and start using it, without having to re-install and
> -format everything?

Plan9 filesystems (on the PC) always live inside a primary DOS partition,
however this may then divided into several plan9 sub-partitions.

I don't believe you can put  plan9 partitions inside a secondary DOS
partition.

-Steve

Re: [9fans] Sensible fossil+venti partitioning

[Richard Miller]

> I don't believe you can put  plan9 partitions inside a secondary DOS
> partition.

Yes, you can.  It's certainly possible to create one or more secondary
plan 9 partitions to add venti to an originally fossil-only install, or
to add some more venti arenas.  disk/fdisk will happily create as many
secondary partitions as you like.