Ok,
I get the point.
Il 23/06/2017 17:42, Ashley Merrick ha scritto:
But your then have a very mismatch of performance across your OSD’s
which is never recommend by CEPH.
It’s all about what you can do with your current boxes capacity to
increase performance across the whole OSD set.
,Ashley
Sent from my iPhone
On 23 Jun 2017, at 10:40 PM, Massimiliano Cuttini <[email protected]
<mailto:[email protected]>> wrote:
Ashley,
but.. instead of use NVMe as a journal, why don't add 2 OSD to the
cluster?
Incresing number of OSD instead of improving performance of actual OSD?
Il 23/06/2017 15:40, Ashley Merrick ha scritto:
Sorry for the not inline reply.
If you can get 6 OSD’s per a NVME as long as your getting a decent
rated NVME your bottle neck will be the NVME but will still improve
over your current bottle neck.
You could add two NVME OSD’s, but their higher performance would be
lost along with the other 12 OSD’s.
,Ashley
Sent from my iPhone
On 23 Jun 2017, at 8:34 PM, Massimiliano Cuttini <[email protected]
<mailto:[email protected]>> wrote:
Hi Ashley,
You could move your Journal to another SSD this would remove the
double write.
If I move the journal to another SSD, I will loss an available OSD,
so this is likely to say improve of *x2* and then decrease of *x½ *...
this should not improve performance in any case on a full SSD disks
system.
Ideally you’d want one or two PCIe NVME in the servers for the
Journal.
This seems a really good Idea, but image that I have only 2 slots
for PCIe and 12 SSD disks.
I image that it's will not be possible place 12 Journal on 2 PCIe
NVME without loss performance..... or yes?
Or if you can hold off a bit then bluestore, which removes the
double write, however is still handy to move some of the services
to a seperate disk.
I hear that bluestore will remove double writing on journal (still
not investigated), but I guess Luminous will be fully tested not
before the end of the year.
About the today system really don't know if moving on a separate
disks will have some impact considering that this is a full SSD
disks system.
Even adding 2 PCIe NVME.... why should not use them as a OSD
instead of journal solo?
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