marcos valentine wrote:> 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 totalAlmost 3GB available on a 48GB machine is very close to "free memory is 0" and "used memory is close to total", which is why I?m wondering what I can get away with :) This free memory can go away in less than a second. Maybe it never will, so I figured why not use as much as possible --- just not too much, and this is borderline.
> This free memory can go away in less than a secondIt's depends of many things. But you need to pay attention on this variables https://mariadb.com/kb/en/library/mariadb-memory-allocation/ In my db servers i use nagios to monitor when "free" and "available" ram is less than 80% warning state and less than 5% critical.> so I figured why not use as much as possible --- just not too much, andthis is borderline. You can use the rule always 80% used for safe. But 20% of 46GB could be too much ram wasted. <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> Livre de v?rus. 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> 2017-11-08 9:56 GMT-02:00 hw <hw at gc-24.de>:> marcos valentine wrote: > >> 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 >> > > Almost 3GB available on a 48GB machine is very close to "free memory is > 0" and "used memory is close to total", which is why I?m wondering what > I can get away with :) > > This free memory can go away in less than a second. Maybe it never will, > so I figured why not use as much as possible --- just not too much, and > this is borderline. > > _______________________________________________ > CentOS mailing list > CentOS at centos.org > https://lists.centos.org/mailman/listinfo/centos >
marcos valentine wrote:>> This free memory can go away in less than a second > > It's depends of many things. But you need to pay attention on this variables > > https://mariadb.com/kb/en/library/mariadb-memory-allocation/Thanks, that?s an interesting page. It tells you to turn off hyperthreading. At some other place on the mariadb website, I?ve been reading it?s generally a good idea to leave it turned on for mariadb. Now which is true?> In my db servers i use nagios to monitor when "free" and "available" ram is > less than 80% warning state and less than 5% critical.Hmm, nagios, yes, I should look into that.>> so I figured why not use as much as possible --- just not too much, and > this is borderline. > > You can use the rule always 80% used for safe. But 20% of 46GB could be too > much ram wasted.It would be a pity to waste it. I think 128GB would be ideal, and the machine might even get that once I get to shuffle the RAM sticks around between different machines. I still wouldn?t want to waste any.