yes, https://www.sebastien-han.fr/blog/2014/08/25/ceph-mix-sata-a
nd-ssd-within-the-same-box/ is enough
don't test on your production env. before you start, backup your cursh map.
ceph osd getcrushmap -o crushmap.bin
below's some hint:
ceph osd getcrushmap -o crushmap.bin
crushtool -d crushmap.bin -o crushmap.txt
vi crushmap.txt
crushtool -c crushmap.txt -o crushmap.bin
ceph osd setcrushmap -i crushmap.bin
=====
ceph osd pool set POOL_NAME crush_ruleset ID
eg. ceph osd pool set ssd_pool crush_rulese 0, ceph osd pool set sata_pool
crush_rulese 1
=====
root ssd {
id -1 # do not change unnecessarily
# weight 0.040
alg straw
hash 0 # rjenkins1
item node1 weight 0.020
item node4 weight 0.020
item node2 weight 0.020
}
rule ssd_rule {
ruleset 1
type replicated
min_size 1
max_size 10
step take ssd
step chooseleaf firstn 0 type host
step emit
}
####### step take ssdXXX <---> root ssdXXX
2017-02-16 22:38 GMT+08:00 Mike Miller <[email protected]>:
> Hi,
>
> thanks all, still I would appreciate hints on a concrete procedure how to
> migrate cephfs metadata to a SSD pool, the SSDs being on the same hosts
> like to spinning disks.
>
> This reference I read:
> https://www.sebastien-han.fr/blog/2014/08/25/ceph-mix-sata-a
> nd-ssd-within-the-same-box/
> Are there other alternatives to this suggested configuration?
>
> I am kind of a little paranoid to start playing around with crush rules in
> the running system.
>
> Regards,
>
> Mike
>
> On 1/5/17 11:40 PM, jiajia zhong wrote:
>
>>
>>
>> 2017-01-04 23:52 GMT+08:00 Mike Miller <[email protected] <mailto:
>> [email protected]>>:
>>
>> Wido, all,
>>
>> can you point me to the "recent benchmarks" so I can have a look?
>> How do you define "performance"? I would not expect cephFS
>> throughput to change, but it is surprising to me that metadata on
>> SSD will have no measurable effect on latency.
>>
>> - mike
>>
>>
>> operations like "ls", "stat", "find" would become faster, the bottleneck
>> is the slow osds which store file data.
>>
>>
>> On 1/3/17 10:49 AM, Wido den Hollander wrote:
>>
>>
>> Op 3 januari 2017 om 2:49 schreef Mike Miller
>> <[email protected] <mailto:[email protected]>>:
>>
>>
>> will metadata on SSD improve latency significantly?
>>
>>
>> No, as I said in my previous e-mail, recent benchmarks showed
>> that storing CephFS metadata on SSD does not improve performance.
>>
>> It still might be good to do since it's not that much data thus
>> recovery will go quickly, but don't expect a CephFS performance
>> improvement.
>>
>> Wido
>>
>> Mike
>>
>> On 1/2/17 11:50 AM, Wido den Hollander wrote:
>>
>>
>> Op 2 januari 2017 om 10:33 schreef Shinobu Kinjo
>> <[email protected] <mailto:[email protected]>>:
>>
>>
>> I've never done migration of cephfs_metadata from
>> spindle disks to
>> ssds. But logically you could achieve this through 2
>> phases.
>>
>> #1 Configure CRUSH rule including spindle disks
>> and ssds
>> #2 Configure CRUSH rule for just pointing to ssds
>> * This would cause massive data shuffling.
>>
>>
>> Not really, usually the CephFS metadata isn't that much
>> data.
>>
>> Recent benchmarks (can't find them now) show that
>> storing CephFS metadata on SSD doesn't really improve
>> performance though.
>>
>> Wido
>>
>>
>>
>> On Mon, Jan 2, 2017 at 2:36 PM, Mike Miller
>> <[email protected]
>> <mailto:[email protected]>> wrote:
>>
>> Hi,
>>
>> Happy New Year!
>>
>> Can anyone point me to specific walkthrough /
>> howto instructions how to move
>> cephfs metadata to SSD in a running cluster?
>>
>> How is crush to be modified step by step such
>> that the metadata migrate to
>> SSD?
>>
>> Thanks and regards,
>>
>> Mike
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