Re: cache tiering deprecated in RHCS 2.0

[Nick Fisk <nick@xxxxxxxxxx>]

 

From: Robert Sanders [mailto:rlsanders@xxxxxxxxx]
Sent: 23 October 2016 16:32
To: nick@xxxxxxxxxx
Cc: ceph-users <ceph-users@xxxxxxxxxxxxxx>
Subject: Re: cache tiering deprecated in RHCS 2.0

 

 

On Oct 23, 2016, at 4:32 AM, Nick Fisk <nick@xxxxxxxxxx> wrote:

 

Unofficial answer but I suspect it is probably correct.

Before Jewel (and later hammer releases), cache tiering reduced performance in pretty much all cases. 

 

 

In it’s current state does this still hold true?  I’ve been spending a lot of time working out a tiering system, and if it’s going to be slow and bug ridden it would save me a lot of time not testing something that’s known to be broken.

 

It works fairly well now in Jewel. The main problems were relating to promoting too fast, this has had a couple of bugs fixed and is now throttled to 4mb/s per OSD. As long as you get the config right for your hardware+workload then you should see a benefit.

 

I’ve been running it now for around 6 months without problems.

 

 

Rob

 

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