I know these machines. Sharding is kind of useless. Set the ssd tb drives up in fastest raid read available, 31 xms xmx, one solr instance. Buy back up ssd drives when you burn one out and it fails over to the master server. Multiple solr instances on one machine makes little sense unless they have different purposes like a ml instance and a text highlighting instance but even then you get no performance improvement
> On Oct 6, 2022, at 12:21 PM, Shawn Heisey <apa...@elyograg.org> wrote: > > On 10/6/22 01:57, Dominique Bejean wrote: >> One of our customer have huge servers >> >> - Bar-metal >> - 64 CPU >> - 512 Gb RAM >> - 6x2Tb disk in RAID 6 (so 2Tb disk space available) >> >> >> I think the best way to optimize resources usage of these servers is to >> install several Solr instances. > > That is not what I would do. > >> Do not configure disks in RAID 6 but, leave 6 standard volumes (more space >> disk, more I/O available) >> Install 3 or 6 solr instances each one using 1 ou 2 disk volumes > > RAID10 will get you the best performance. Six 2TB drives in RAID10 has 6TB > of total space. The ONLY disadvantage that RAID10 has is that you pay for > twice the usable storage. Disks are relatively cheap, though hard to get in > quantity these days. I would recommend going with the largest stripe size > your hardware can support. 1MB is typically where that maxes out. > > Any use of RAID5 or RAID6 has two major issues: 1) A serious performance > problem that also affects reads if there are ANY writes happening. 2) If a > disk fails, performance across the board is terrible. When the bad disk is > replaced, performance is REALLY terrible as long as a rebuild is happening, > and I have seen a RAID5/6 rebuild take 24 to 48 hours with 2TB disks on a > busy array. It would take even longer with larger disks. > >> What I am not sure is how MMapDirectory will work with several Solr >> instances. Will off heap memory correctly managed and shared between >> several Solr instances ? > > With symlinks or multiple mount points in the solr home, you can have a > single instance handle indexes on multiple storage devices. One instance has > less overhead, particularly in memory, than multiple instances. Off heap > memory for the disk cache should function as expected with multiple instances > or one instances. > > Thanks, > Shawn >
