Hi everyone,
I just started to look at the documentation of Ceph and I've hit
something I don't understand.
It's about something on http://ceph.com/docs/master/architecture/
"""
use the following steps to compute PG IDs.
The client inputs the pool ID and the object ID. (e.g., pool =
?liverpool? and object-id = ?john?)
CRUSH takes the object ID and hashes it.
--> CRUSH calculates the hash modulo the number of OSDs. (e.g., 0x58)
to get a PG ID. <---
CRUSH gets the pool ID given the pool name (e.g., ?liverpool? = 4)
CRUSH prepends the pool ID to the PG ID (e.g., 4.0x58).
"""
Shouldn't this be 'CRUSH calculates the hash modulo the the number of
PGs to get a PG ID' ?
But then what happens if you add more PGs to the pool? Then most of
the data will be reallocated to another PG?
Thanks for your help!
Kind Regards,
Kenneth Waegeman
_______________________________________________
ceph-users mailing list
ceph-users@xxxxxxxxxxxxxx
http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
