Hello, Thanks for your reply, when you say latest's version do you .6 and not .5? The use case is large scale storage VM's, which may have a burst of high write's during new storage being loaded onto the environment, looking to place the SSD Cache in front currently with a replica of 3 and useable size of 1.5TB. Looking to run in Read-forward Mode, so reads will come direct from the OSD layer where there is no issue with current read performance, however any large write's will first go to the SSD and then at a later date flushed to the OSD's as the SSD cache hits for example 60%. So the use case is not as such to store hot DB data that will stay there, but to act as a temp sponge for high but short writes in bursts. ,Ashley -----Original Message----- From: Christian Balzer [mailto:chibi@xxxxxxx] Sent: Wednesday, 2 November 2016 11:48 AM To: ceph-users@xxxxxxxx Cc: Ashley Merrick <ashley@xxxxxxxxxxxxxx> Subject: Re: Hammer Cache Tiering Hello, On Tue, 1 Nov 2016 15:07:33 +0000 Ashley Merrick wrote: > Hello, > > Currently using a Proxmox & CEPH cluster, currently they are running on Hammer looking to update to Jewel shortly, I know I can do a manual upgrade however would like to keep what is tested well with Proxmox. > > Looking to put a SSD Cache tier in front, however have seen and read there has been a few bug's with Cache Tiering causing corruption, from what I read all fixed on Jewel however not 100% if they have been pushed to Hammer (even though is still not EOL for a little while). > You will want to read at LEAST the last two threads about "cache tier" in this ML, more if you can. > Is anyone running Cache Tiering on Hammer in production and had no issues, or is anyone aware of any bugs' / issues that means I should hold off till I upgrade to Jewel, or any reason basically to hold off for a month or so to update to Jewel before enabling a cache tier. > The latest Hammer should be fine, 0.94.5 has been working for me a long time, 0.94.6 is DEFINITELY to be avoided at all costs. A cache tier is a complex beast. Does it fit your needs/use patterns, can you afford to make it large enough to actually fit all your hot data in it? Jewel has more control knobs to help you, so unless you are 100% sure that you know what you're doing or have a cache pool in mind that's as large as your current used data, waiting for Jewel might be a better proposition. Of course the lack of any official response to the last relevant thread here about the future of cache tiering makes adding/designing a cache tier an additional challenge... Christian -- Christian Balzer Network/Systems Engineer chibi@xxxxxxx Global OnLine Japan/Rakuten Communications http://www.gol.com/ _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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