Disk cache is not recommended for databases servers. it'll slow down the performance. More ram equals more performance. This link help me understand memory usage on linux. https://www.linuxatemyram.com/ Basically you need yo worry about free memory is close to 0 used memory is close to total available memory (or "free + buffers/cache") has enough room (let's say, 20%+ of total) swap used does not change Warning signs of a genuine low memory situation that you may want to look into: available memory (or "free + buffers/cache") is close to zero swap used increases or fluctuates dmesg | grep oom-killer shows the OutOfMemory-killer at work You can monitory swap with "vmsat 1" <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> Livre de vírus. www.avast.com <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>. <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> 2017-11-04 12:05 GMT-02:00 hw <hw at gc-24.de>: > > Hi, > > is this ok for a database server, or do I need to turn the memory allowance > down? The machine has 48GB and mariadb is allowed about 40. The > machine is a dedicated database server. > > Mysql seems to go up to what top says is virtually allocated under some > circumstances; I don´t know what mariadb does. I don´t want anything > get killed because memory runs out. Swap should prevent that anyway, > but perhaps I went a bit higher than I should? > > Usual advice is to use 80%, and there are probably reasons for that. > Perhaps it´s better to allow for more disk cache? > > > KiB Mem : 49449424 total, 291772 free, 45891836 used, 3265816 buff/cache > KiB Swap: 16777212 total, 16742928 free, 34284 used. 2985816 avail Mem > > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND > 4138 mysql 20 0 48.908g 0.042t 14064 S 0.0 91.8 111:23.17 mysqld > _______________________________________________ > CentOS mailing list > CentOS at centos.org > https://lists.centos.org/mailman/listinfo/centos >