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
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 wrote:
> From https://help.ubuntu.com/community/SwapFaq
> "
> swappiness=0 tells the kernel to avoid swapping process
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 |
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
> Hello
>
> We have 6 node cluster (cassandra 0.8.10). On one node i increase java
> heap size to 6GB, and n
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
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
> I know:-) but this is not answer:-(. I found that on other nodes there
> still about 3G
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
Its recommended to disable swap entirely when you run Cassandra on a server.
2012/4/14 ruslan usifov
> I forgot to say that system have 24GB of phis memory
>
>
> 2012/4/14 ruslan usifov
>
>> Hello
>>
>> We have 6 node cluster (cassandra 0.8.10). On one node i increase java
>> heap size to 6GB,
I forgot to say that system have 24GB of phis memory
2012/4/14 ruslan usifov
> 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
>
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 21702
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