Re: swap grows
Thanks for link. But for me still present question about free memory. In out cluster we have 200 IOPS in peaks, but still have about 3GB of free memory on each server (cluster have 6 nodes tho there are 3*6=18 GB of unused memry). I think that OS must fill all memory with pagecache (we do backups throw DirectIO) of SStables, but it doesn't do that and i doesn't understand why. I can't find any sysctl that can tune pagecache thresholds or ratio. Any suggestion 2012/4/18 Jonathan Ellis jbel...@gmail.com what-is-the-linux-kernel-parameter-vm-swappinesshttp://www.linuxvox.com/2009/10/what-is-the-linux-kernel-parameter-vm-swappiness
Re: swap grows
Swappiness is actually a fairly weak hint to linux: http://www.linuxvox.com/2009/10/what-is-the-linux-kernel-parameter-vm-swappiness On Sat, Apr 14, 2012 at 1:39 PM, aaron morton aa...@thelastpickle.com wrote: From https://help.ubuntu.com/community/SwapFaq swappiness=0 tells the kernel to avoid swapping processes out of physical memory for as long as possible If you have swap enabled at some point the OS may swap out pages, even if swappiness is 0 and you have free memory. Disable swap entirely if you want to avoid this. Cheers - Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 15/04/2012, at 1:37 AM, R. Verlangen wrote: Maybe it has got something to do with swapiness, it's something you can configure, more info here: https://www.linux.com/news/software/applications/8208-all-about-linux-swap-space 2012/4/14 ruslan usifov ruslan.usi...@gmail.com I know:-) but this is not answer:-(. I found that on other nodes there still about 3GB (on node with JAVA_HEAP=6GB free memory also 3GB) of free memory but there JAVA_HEAP=5G, so this looks like some sysctl (/proc/sys/vm???) ratio (about 10%(3 / 24 * 100)), i don't known which, anybody can explain this situation 2012/4/14 R. Verlangen ro...@us2.nl Its recommended to disable swap entirely when you run Cassandra on a server. 2012/4/14 ruslan usifov ruslan.usi...@gmail.com I forgot to say that system have 24GB of phis memory 2012/4/14 ruslan usifov ruslan.usi...@gmail.com Hello We have 6 node cluster (cassandra 0.8.10). On one node i increase java heap size to 6GB, and now at this node begin grows swap, but system have about 3GB of free memory: root@6wd003:~# free total used free shared buffers cached Mem: 24733664 21702812 3030852 0 6792 13794724 -/+ buffers/cache: 7901296 16832368 Swap: 1998840 2352 1996488 And swap space slowly grows, but i misunderstand why? PS: We have JNA mlock, and set vm.swappiness = 0 PS: OS ubuntu 10.0.4(2.6.32-40-generic) -- With kind regards, Robin Verlangen www.robinverlangen.nl -- With kind regards, Robin Verlangen www.robinverlangen.nl -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
Re: swap grows
BTW: Are you sure system doing wrong? System may save some pages to swap not removing them from RAM simply to have possibility to remove them later fast if needed. 2012/4/14 ruslan usifov ruslan.usi...@gmail.com Hello We have 6 node cluster (cassandra 0.8.10). On one node i increase java heap size to 6GB, and now at this node begin grows swap, but system have about 3GB of free memory: root@6wd003:~# free total used free sharedbuffers cached Mem: 24733664 217028123030852 0 6792 13794724 -/+ buffers/cache:7901296 16832368 Swap: 1998840 23521996488 And swap space slowly grows, but i misunderstand why? PS: We have JNA mlock, and set vm.swappiness = 0 PS: OS ubuntu 10.0.4(2.6.32-40-generic) -- Best regards, Vitalii Tymchyshyn
Re: swap grows
Not i don't sure about this:-)) I don't have very good knowns about Linux
VM managment. And for me looks very stange that swap grows, but not any
swap activity (i monitor it throw follow vmstat -s | grep 'pages swapped
out' | awk '{ print $1 }' and vmstat -s | grep 'pages swapped in' | awk '{
print $1 }'). So looks like that you right, and i has filled up my
knowledge:-))
2012/4/15 Віталій Тимчишин tiv...@gmail.com
BTW: Are you sure system doing wrong? System may save some pages to swap
not removing them from RAM simply to have possibility to remove them later
fast if needed.
2012/4/14 ruslan usifov ruslan.usi...@gmail.com
Hello
We have 6 node cluster (cassandra 0.8.10). On one node i increase java
heap size to 6GB, and now at this node begin grows swap, but system have
about 3GB of free memory:
root@6wd003:~# free
total used free sharedbuffers cached
Mem: 24733664 217028123030852 0 6792 13794724
-/+ buffers/cache:7901296 16832368
Swap: 1998840 23521996488
And swap space slowly grows, but i misunderstand why?
PS: We have JNA mlock, and set vm.swappiness = 0
PS: OS ubuntu 10.0.4(2.6.32-40-generic)
--
Best regards,
Vitalii Tymchyshyn
Re: swap grows
Its recommended to disable swap entirely when you run Cassandra on a server. 2012/4/14 ruslan usifov ruslan.usi...@gmail.com I forgot to say that system have 24GB of phis memory 2012/4/14 ruslan usifov ruslan.usi...@gmail.com Hello We have 6 node cluster (cassandra 0.8.10). On one node i increase java heap size to 6GB, and now at this node begin grows swap, but system have about 3GB of free memory: root@6wd003:~# free total used free sharedbuffers cached Mem: 24733664 217028123030852 0 6792 13794724 -/+ buffers/cache:7901296 16832368 Swap: 1998840 23521996488 And swap space slowly grows, but i misunderstand why? PS: We have JNA mlock, and set vm.swappiness = 0 PS: OS ubuntu 10.0.4(2.6.32-40-generic) -- With kind regards, Robin Verlangen www.robinverlangen.nl
Re: swap grows
I know:-) but this is not answer:-(. I found that on other nodes there still about 3GB (on node with JAVA_HEAP=6GB free memory also 3GB) of free memory but there JAVA_HEAP=5G, so this looks like some sysctl (/proc/sys/vm???) ratio (about 10%(3 / 24 * 100)), i don't known which, anybody can explain this situation 2012/4/14 R. Verlangen ro...@us2.nl Its recommended to disable swap entirely when you run Cassandra on a server. 2012/4/14 ruslan usifov ruslan.usi...@gmail.com I forgot to say that system have 24GB of phis memory 2012/4/14 ruslan usifov ruslan.usi...@gmail.com Hello We have 6 node cluster (cassandra 0.8.10). On one node i increase java heap size to 6GB, and now at this node begin grows swap, but system have about 3GB of free memory: root@6wd003:~# free total used free sharedbuffers cached Mem: 24733664 217028123030852 0 6792 13794724 -/+ buffers/cache:7901296 16832368 Swap: 1998840 23521996488 And swap space slowly grows, but i misunderstand why? PS: We have JNA mlock, and set vm.swappiness = 0 PS: OS ubuntu 10.0.4(2.6.32-40-generic) -- With kind regards, Robin Verlangen www.robinverlangen.nl
Re: swap grows
Maybe it has got something to do with swapiness, it's something you can configure, more info here: https://www.linux.com/news/software/applications/8208-all-about-linux-swap-space 2012/4/14 ruslan usifov ruslan.usi...@gmail.com I know:-) but this is not answer:-(. I found that on other nodes there still about 3GB (on node with JAVA_HEAP=6GB free memory also 3GB) of free memory but there JAVA_HEAP=5G, so this looks like some sysctl (/proc/sys/vm???) ratio (about 10%(3 / 24 * 100)), i don't known which, anybody can explain this situation 2012/4/14 R. Verlangen ro...@us2.nl Its recommended to disable swap entirely when you run Cassandra on a server. 2012/4/14 ruslan usifov ruslan.usi...@gmail.com I forgot to say that system have 24GB of phis memory 2012/4/14 ruslan usifov ruslan.usi...@gmail.com Hello We have 6 node cluster (cassandra 0.8.10). On one node i increase java heap size to 6GB, and now at this node begin grows swap, but system have about 3GB of free memory: root@6wd003:~# free total used free sharedbuffers cached Mem: 24733664 217028123030852 0 6792 13794724 -/+ buffers/cache:7901296 16832368 Swap: 1998840 23521996488 And swap space slowly grows, but i misunderstand why? PS: We have JNA mlock, and set vm.swappiness = 0 PS: OS ubuntu 10.0.4(2.6.32-40-generic) -- With kind regards, Robin Verlangen www.robinverlangen.nl -- With kind regards, Robin Verlangen www.robinverlangen.nl
Re: swap grows
From https://help.ubuntu.com/community/SwapFaq swappiness=0 tells the kernel to avoid swapping processes out of physical memory for as long as possible If you have swap enabled at some point the OS may swap out pages, even if swappiness is 0 and you have free memory. Disable swap entirely if you want to avoid this. Cheers - Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 15/04/2012, at 1:37 AM, R. Verlangen wrote: Maybe it has got something to do with swapiness, it's something you can configure, more info here: https://www.linux.com/news/software/applications/8208-all-about-linux-swap-space 2012/4/14 ruslan usifov ruslan.usi...@gmail.com I know:-) but this is not answer:-(. I found that on other nodes there still about 3GB (on node with JAVA_HEAP=6GB free memory also 3GB) of free memory but there JAVA_HEAP=5G, so this looks like some sysctl (/proc/sys/vm???) ratio (about 10%(3 / 24 * 100)), i don't known which, anybody can explain this situation 2012/4/14 R. Verlangen ro...@us2.nl Its recommended to disable swap entirely when you run Cassandra on a server. 2012/4/14 ruslan usifov ruslan.usi...@gmail.com I forgot to say that system have 24GB of phis memory 2012/4/14 ruslan usifov ruslan.usi...@gmail.com Hello We have 6 node cluster (cassandra 0.8.10). On one node i increase java heap size to 6GB, and now at this node begin grows swap, but system have about 3GB of free memory: root@6wd003:~# free total used free sharedbuffers cached Mem: 24733664 217028123030852 0 6792 13794724 -/+ buffers/cache:7901296 16832368 Swap: 1998840 23521996488 And swap space slowly grows, but i misunderstand why? PS: We have JNA mlock, and set vm.swappiness = 0 PS: OS ubuntu 10.0.4(2.6.32-40-generic) -- With kind regards, Robin Verlangen www.robinverlangen.nl -- With kind regards, Robin Verlangen www.robinverlangen.nl
swap grows
Hello We have 6 node cluster (cassandra 0.8.10). On one node i increase java heap size to 6GB, and now at this node begin grows swap, but system have about 3GB of free memory: root@6wd003:~# free total used free sharedbuffers cached Mem: 24733664 217028123030852 0 6792 13794724 -/+ buffers/cache:7901296 16832368 Swap: 1998840 23521996488 And swap space slowly grows, but i misunderstand why? PS: We have JNA mlock, and set vm.swappiness = 0 PS: OS ubuntu 10.0.4(2.6.32-40-generic)
Re: swap grows
I forgot to say that system have 24GB of phis memory 2012/4/14 ruslan usifov ruslan.usi...@gmail.com Hello We have 6 node cluster (cassandra 0.8.10). On one node i increase java heap size to 6GB, and now at this node begin grows swap, but system have about 3GB of free memory: root@6wd003:~# free total used free sharedbuffers cached Mem: 24733664 217028123030852 0 6792 13794724 -/+ buffers/cache:7901296 16832368 Swap: 1998840 23521996488 And swap space slowly grows, but i misunderstand why? PS: We have JNA mlock, and set vm.swappiness = 0 PS: OS ubuntu 10.0.4(2.6.32-40-generic)
