Maybe I am doing it wrong but I am using NVMe for primary storage and ass tons of ram for arc.
I think L2ARC is relegated to the highly budget oriented plays these days as RAM is soooo cheap. Buy some more ram and fooor-get-about it. J. Sent from my iPhone > On Aug 23, 2018, at 1:07 PM, Sanjay Nadkarni <[email protected]> > wrote: > > Found this link for FreeBSD too > http://www.brendangregg.com/blog/2015-03-10/freebsd-flame-graphs.html > > -Sanjay > > > > >> On 8/23/18 1:02 PM, Sanjay Nadkarni wrote: >> Would be useful if you could get flamegraphs when you run into this. See >> https://github.com/brendangregg/FlameGraph >> >> Once we have that, the we can have a better understanding of what's going on >> and we can dtrace it further to figure it out. >> >> -Sanjay >> >> >> >> >>> On 8/23/18 5:47 AM, w.kruzel via openzfs-developer wrote: >>> It's interesting what you said, as I have two examples (both with different >>> Intel nvme disks) that show otherwise. >>> >>> Being nvme, I was expecting read performance from L2ARC at 2GB/s+ levels, >>> yet I only get ~200MB/s read speeds when I certainly know it is being read >>> from L2ARC. >>> >>> When tested (details in my earlier post), I can get the same speed with >>> nvmecontrol perftest that is single threaded. >>> Multi threaded perftest gives 2GB/s + output. >>> >>> I also have this raised with FreeNAS where one of their devs tested it on >>> other make L2ARC he had installed and confirmed that it looks like single >>> threaded process. >>> >>> Can someone look into this please? >>> It is a major performance hit for L2ARC, making it not really fit for >>> purpose :( >>> >>> Kind regards, >>> Wojciech Kruzel > > openzfs / openzfs-developer / see discussions + participants + delivery > options Permalink ------------------------------------------ openzfs: openzfs-developer Permalink: https://openzfs.topicbox.com/groups/developer/Tf62628db027682f7-M9979dec7dbb9660060df7a91 Delivery options: https://openzfs.topicbox.com/groups/developer/subscription
