Hi,
On 02/28/2012 10:50 AM, Oliver Francke wrote:
Well,
On 02/28/2012 10:42 AM, Wido den Hollander wrote:
Hi,
On 02/28/2012 10:35 AM, Oliver Francke wrote:
Hi *,
well, there was once a comment on our layout in means of "too many
pools".
Our setup is to have a pool per customer, to simplify the view on used
storage
capacity.
So, if we have - in a couple of months, we hope - more then some hundred
customers, this setup was not recommended, cause the whole system is not
designed for handling that. ( Sage)
What does "not recommended" mean? Is it, that per OSD the used memory
will be
too high?
Yes. Every new pool you create will consume some memory on the OSD. So
if you start creating a lot of pools, you will also start consuming
more and more memory.
I haven't followed this lately, but that is the current information I
have.
The number of objects in a pool is also not a problem, you can have
millions without any issues. It's the number of pools which will haunt
you later on.
thnx for the quick reply, so if we can imagine, that the number of pool
per OSD is
the limiting factor, we shall not have more than let's say ~100, means,
we shall be
safe.
IIRC the number of pools is a problem, but for every pool you have a
number of Placement Groups (PG's) (pg_num). Each PG eats a small amount
of memory.
As the number of OSD's increases you also want to increase the number of
PG's, this improves performance.
But as you have more PG's per pool, you start increasing memory usage.
Now, PG's will be spread out over your OSD's, but it could still
increase the usage.
This probably won't be a problem with 500 pools, or maybe a thousand
pools (but it could), but going above that could be a problem.
Wido
Wido
best regards,
Oliver.
Is this a general performance issue?
Well, if we read "pool", this gave us the basic idea/concept to put all
per-customers
data into it.
Please sched some light in 8-)
Kind regards,
Oliver.
--
To unsubscribe from this list: send the line "unsubscribe ceph-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
