>> [...] a long standing problem. When lots of writes to many >> files are sent in a short time the kernel gets stuck and >> stops sending write requests to the disks. [...] A simple way >> to reproduce: expand a kernel source tree, like xzcat >> linux-6.5.tar.xz | tar x -f - That is a well known (ideally...) consequence of misconfiguring both physical storage and the Linux flusher cache so there is a high chance of post-saturation congestion under load. https://www.sabi.co.uk/blog/anno05-4th.html?051105#051105 > [...] I had two arrays with it, one on SSDs and one on HDDs. > The HDD array exhibited the problem almost exclusively [...] If an HDD set is misconfigured so that it reaches post saturation congestion of IOPS much sooner than problems with that and the consequences of flusher cache misconfiguration will happen much more frequently. Usually to sustain the same number of workload IOPS one needs at least 10 times more HDDs than SSDs.
