Thread: RHEL-8 Kernel Settings
Hello I’m looking for assistance in determining kernel setting for a VM RHEL-8 linux server running postgresql-13. I have 3 server groupings 1) 2 vcpu’s 8gb memory 2) 4 cpu’s 16gb memory 3) 8 cpu’s 32gb memory I’ve read various articles and the PostgreSQL documentation . Does anyone have practical experiences doing this kind ofset up Do kernel setting requirements change based on the number of cpu’s and amount of memory? I’ve not read any mention ofthis. Regards John W
On Thu, 2021-06-10 at 13:06 -0500, John Wiencek wrote: > I’m looking for assistance in determining kernel setting for a VM RHEL-8 linux server running postgresql-13. > > I have 3 server groupings > > 1) 2 vcpu’s 8gb memory > 2) 4 cpu’s 16gb memory > 3) 8 cpu’s 32gb memory > > I’ve read various articles and the PostgreSQL documentation . Does anyone have practical experiences doing this kindof set up > > Do kernel setting requirements change based on the number of cpu’s and amount of memory? I’ve not read any mention ofthis. I recommend setting vm.overcommit_memory = 2 vm.overcommit_ratio (the correct value depends on your swap) vm.swappiness = 0 Also, disable Transparent Hugepages. Yours, Laurenz Albe -- Cybertec | https://www.cybertec-postgresql.com
On Fri, Jun 11, 2021 at 08:56:13AM +0200, Laurenz Albe wrote: > [...] > I recommend setting > > vm.overcommit_memory = 2 Be careful with this though, most applications no not allocate memory as thoughtfully as Postgres - so if your server is running any other kind of service/software in addition to Postgres, you should make sure that can survive Linux not overcommitting like there's no tomorrow, too. -- with best regards: - Johannes Truschnigg ( johannes@truschnigg.info ) www: https://johannes.truschnigg.info/ phone: +43 650 2 133337 xmpp: johannes@truschnigg.info
Attachment
Other than HugePages are any other settings determined by the amount of memory on a server? John Sent from my iPad > On Jun 11, 2021, at 1:56 AM, Laurenz Albe <laurenz.albe@cybertec.at> wrote: > > On Thu, 2021-06-10 at 13:06 -0500, John Wiencek wrote: >> I’m looking for assistance in determining kernel setting for a VM RHEL-8 linux server running postgresql-13. >> >> I have 3 server groupings >> >> 1) 2 vcpu’s 8gb memory >> 2) 4 cpu’s 16gb memory >> 3) 8 cpu’s 32gb memory >> >> I’ve read various articles and the PostgreSQL documentation . Does anyone have practical experiences doing this kindof set up >> >> Do kernel setting requirements change based on the number of cpu’s and amount of memory? I’ve not read any mentionof this. > > I recommend setting > > vm.overcommit_memory = 2 > vm.overcommit_ratio (the correct value depends on your swap) > vm.swappiness = 0 > > Also, disable Transparent Hugepages. > > Yours, > Laurenz Albe > -- > Cybertec | https://www.cybertec-postgresql.com >