Hi,
El 25/11/18 a las 18:23, Виталий Филиппов escribió:
Ok... That's better than previous thread with file download where the
topic starter suffered from normal only-metadata-journaled fs...
Thanks for the link, it would be interesting to repeat similar tests.
Although I suspect it shouldn't
Hello Anton,
we have some bad experience with consumer disks. They tend to fail quite
early and sometimes have extrem poor performance in Ceph workloads.
If possible, spend some money on reliable Samsung PM/SM863a SSDs. However a
customer of us uses the WD Blue 1TB SSDs and seems to be quite
At least when I run a simple O_SYNC random 4k write test with a random
Intel 545s SSD plugged in through USB3-SATA adapter (UASP), pull USB cable
out and then recheck written data everything is good and nothing is lost
(however iops are of course low, 1100-1200)
--
With best regards,
Ok... That's better than previous thread with file download where the topic
starter suffered from normal only-metadata-journaled fs... Thanks for the link,
it would be interesting to repeat similar tests. Although I suspect it
shouldn't be that bad... at least not all desktop SSDs are that
On 25 Nov 2018, at 15.17, Vitaliy Filippov wrote:
>
> All disks (HDDs and SSDs) have cache and may lose non-transactional writes
> that are in-flight. However, any adequate disk handles fsync's (i.e SATA
> FLUSH CACHE commands). So transactional writes should never be lost, and in
> Ceph ALL
Ceph issues fsync's all the time
...and, of course, it has journaling :) (only fsync is of course not
sufficient)
with enterprise SSDs which have capacitors fsync just becomes a no-op and
thus transactional write performance becomes the same as non-transactional
(i.e. 10+ times faster
the real risk is the lack of power loss protection. Data can be
corrupted on unflean shutdowns
it's not! lack of "advanced power loss protection" only means lower iops
with fsync, but not the possibility of data corruption
"advanced power loss protection" is basically the synonym for
>> the real risk is the lack of power loss protection. Data can be
>> corrupted on unflean shutdowns
>
> it's not! lack of "advanced power loss protection" only means lower iops
> with fsync, but not the possibility of data corruption
>
> "advanced power loss protection" is basically the synonym
On 24 Nov 2018, at 18.09, Anton Aleksandrov wrote
We plan to have data on dedicate disk in each node and my question is
about WAL/DB for Bluestore. How bad would it be to place it on
system-consumer-SSD? How big risk is it, that everything will get
"slower than using spinning HDD for the
> On 24 Nov 2018, at 18.09, Anton Aleksandrov wrote
> We plan to have data on dedicate disk in each node and my question is about
> WAL/DB for Bluestore. How bad would it be to place it on system-consumer-SSD?
> How big risk is it, that everything will get "slower than using spinning HDD
>
As it’s consumer hardware / old I am guessing your only be using 1Gbps for
the network.
If so that will definitely be your bottle neck across the whole environment
having both client and replication data sharing a single 1Gbps.
Your SSD’s will sit mostly idle, if you have 10Gbps then different
Hello community,
We are building CEPH cluster on pretty old (but free) hardware. We will
have 12 nodes with 1 OSD per node and migrate data from single RAID5
setup, so our traffic is not very intense, we basically need more space
and possibility to expand it.
We plan to have data on
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