Hello,
On Mon, 7 Mar 2016 00:38:46 + Adrian Saul wrote:
> > >The Samsungs are the 850 2TB
> > > (MZ-75E2T0BW). Chosen primarily on price.
> >
> > These are spec'ed at 150TBW, or an amazingly low 0.04 DWPD (over 5
> > years). Unless you have a read-only cluster, you will wind up spending
>
> >The Samsungs are the 850 2TB
> > (MZ-75E2T0BW). Chosen primarily on price.
>
> These are spec'ed at 150TBW, or an amazingly low 0.04 DWPD (over 5 years).
> Unless you have a read-only cluster, you will wind up spending MORE on
> replacing them (and/or loosing data when 2 fail at the same time)
Hello,
On Thu, 3 Mar 2016 23:26:13 + Adrian Saul wrote:
>
> > Samsung EVO...
> > Which exact model, I presume this is not a DC one?
> >
> > If you had put your journals on those, you would already be pulling
> > your hairs out due to abysmal performance.
> >
> > Also with Evo ones, I'd be
> Samsung EVO...
> Which exact model, I presume this is not a DC one?
>
> If you had put your journals on those, you would already be pulling your hairs
> out due to abysmal performance.
>
> Also with Evo ones, I'd be worried about endurance.
No, I am using the P3700DCs for journals. The
s-boun...@lists.ceph.com] On Behalf Of
> Jan Schermer
> Sent: 03 March 2016 14:38
> To: RDS <rs3...@me.com>
> Cc: ceph-users@lists.ceph.com
> Subject: Re: [ceph-users] Ceph RBD latencies
>
> I think the latency comes from journal flushing
>
> Try tuning
>
> filestore min syn
I think the latency comes from journal flushing
Try tuning
filestore min sync interval = .1
filestore max sync interval = 5
and also
/proc/sys/vm/dirty_bytes (I suggest 512MB)
/proc/sys/vm/dirty_background_bytes (I suggest 256MB)
See if that helps
It would be useful to see the job you are
A couple of suggestions:
1) # of pgs per OSD should be 100-200
2) When dealing with SSD or Flash, performance of these devices hinge on how
you partition them and how you tune linux:
a) if using partitions, did you align the partitions on a 4k
boundary? I start at sector 2048 using
Hello,
On Thu, 3 Mar 2016 07:41:09 + Adrian Saul wrote:
> Hi Ceph-users,
>
> TL;DR - I can't seem to pin down why an unloaded system with flash based
> OSD journals has higher than desired write latencies for RBD devices.
> Any ideas?
>
>
> I am developing a storage system based on
