Hi,
Christian Balzer wrote:
>> thanks for the feedback regarding the network questions. Currently I try
>> to solve the question of how much memory, cores and GHz for OSD nodes
>> and Monitors.
>>
>> My research so far:
>>
>> OSD nodes: 2 GB RAM, 2 GHz, 1 Core (?) per OSD
>>
> RAM is enough, but more helps (page cache on the storage node makes the
> reads of hot objects quite fast and prevents concurrent access to the
> disks).
Personally, I have seen a different rule for the RAM: "1GB for each 1TB
of OSD daemons". This is I understand in this doc:
http://ceph.com/docs/master/start/hardware-recommendations/#minimum-hardware-recommendations
So, for instance, with (it's just a stupid example):
- 4 OSD daemons of 6TB and
- 5 OSD daemons of 1TB
The needed RAM would be:
1GB x (4 x 6) + 1GB x (5 x 1) = 29GB for the RAM
Is it correct? Because if I follow the "2GB RAM per OSD" rule, I just need:
2GB x 9 = 18GB.
Which rule is correct?
> 1GHz or so for per pure HDD based OSD, at least 2GHz for HDD OSDs with SSD
> journals, as much as you can afford for entirely SSD based OSDs.
Are there links about the "at least 2Ghz per OSD with SSD journal", because
I have never seen that except in this mailing list. For instance in the
"HARDWARE CONFIGURATION GUIDE" of Inktank, it is just indicated: "one GHz
per OSD" (https://ceph.com/category/resources/).
Why should SSD journals increase the needed CPU?
--
François Lafont
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