By the way, here is a useful tool to calculate pg.
http://ceph.com/pgcalc/
Best wishes,
Mika
2015-11-18 11:46 GMT+08:00 Vickie ch :
> Hi wah peng,
> Hope you don't mind. Just for reference.
> A extreme case. If your ceph cluster have 3 osd disks on different osd
> server.
> Set pg number is
Hi wah peng,
Hope you don't mind. Just for reference.
A extreme case. If your ceph cluster have 3 osd disks on different osd
server.
Set pg number is 10240.(Just example) That's mean all these pg will create
on 3 disks.
Lost one OSD also means a lot of pg lost too. It may bring some trouble for
r
"Learning Ceph" book gives us the following formula:
PGs = OSDs × 100 / (replicas × pools)
Saying, you have 10 OSDs and 5 pools with replica 2, you get:
PGs = 10 × 100 / (2 × 5) = 100 PGs (per pool)
It is also advised to round PGs count up to nearest power of 2. In this
case, to 128.
In typ
f Of
Francois Lafont
Sent: Friday, November 13, 2015 4:34 AM
To: ceph-users@lists.ceph.com
Subject: Re: [ceph-users] about PG_Number
Hi,
On 13/11/2015 09:13, Vickie ch wrote:
> If you have a large amount of OSDs but less pg number. You will find
> your data write unevenly.
> Some OSD h
In our experience too few PGS leads to non-uniform disk load as well. We
had lots of blocked IO when many of the disks were idle because there were
and equal number always at 100% utilized. Lots of blocked IO when OSDS
restarted and scanning the huge PGS (data). Scrubs were also painful for
similar
Hi,
On 13/11/2015 09:13, Vickie ch wrote:
> If you have a large amount of OSDs but less pg number. You will find your
> data write unevenly.
> Some OSD have no change to write data.
> In the other side, pg number too large but OSD number too small that have a
> chance to cause data lost.
Data lo
why data lost happens? thanks.
On 2015/11/13 星期五 16:13, Vickie ch wrote:
In the other side, pg number too large but OSD number too small that
have a chance to cause data lost.
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Hi wah peng,
Just a thought.
If you have a large amount of OSDs but less pg number. You will find your
data write unevenly.
Some OSD have no change to write data.
In the other side, pg number too large but OSD number too small that have a
chance to cause data lost.
Best wishes,
Mika
2015-11
Hello,
what's the disadvantage if setup PG_Number too large or too small
against OSD number?
Thanks.
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