Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
> On 20 Oct 2015, at 19:20, Digimer <lists at alteeve.ca> wrote: > > On 20/10/15 12:25 PM, Joeri Casteels wrote: >> >>> On 20 Oct 2015, at 17:47, Lionel Sausin <ls at numerigraphe.com> wrote: >>> >>> Le 20/10/2015 17:30, Joeri Casteels a écrit : >>>>> Protocol A an async, C is sync. So you're probably hitting the network >>>>> limit on C. >>>> I don’t think so since it has a direct 20G trunk in-between with perf i get 19.6Gbit/s on single threat. With A (async when i monitor the network it also hits 2x the network speed as C does) >>> "sync" means the round-trip time (down to the remote disks) is what counts, not the bandwidth. >> So what causes the 1/2 difference then if i read on forum’s most people don’t even see a speed difference between protocol A and C… btw both’s primary and slave node are identical hardware wise so it’s not that the disks are the limiting factor. > > It could easily be the hardware, or configuration, or any number of things. > > To diagnose, you'll want to test each node's storage on its own, test > the network links in isolation, etc. You need to find the location of > the performance issue (or confirm there is no issue) before you burn > time debugging higher-level applications like DRBD. > I did all the debugging on lower level before posting here, sorry i should have mentioned this but i thought that was logical :-) So no bottlenecks on local level and also not on network isolated level… > Protocol A says to call the write complete when it's on the local node's > network send buffers, so the slow-down could be on the peer's network > receive buffers. Try testing Protocol B. That calls the write complete > when it's received by the peer, but not yet committed to persistent storage. I tried protocol B and also have the same effect as protocol C so 1/2 performance drop compared to protocol A… i played with send and receive buffers but still no change… I did find a performance increase today with the al-extents but that’s on all protocols so still end up with 1/2 the performance on protocol B and C. > > -- > Digimer > Papers and Projects: https://alteeve.ca/w/ > What if the cure for cancer is trapped in the mind of a person without > access to education?