Lot more swapping in stable/10 with ZFS

[Volodymyr Kostyrko]

28.01.2014 18:33, Andriy Gapon wrote:
> on 28/01/2014 17:37 Volodymyr Kostyrko said the following:
>> 26.01.2014 12:06, Nagy, Attila wrote:
>>> Hi,
>>>
>>> Running stable/10 at r261157 (and earlier too), I've noticed that it swaps
>>> much more than previous (stable/9) versions.
>>> Current top output from such a machine:
>>> Mem: 251M Active, 21M Inact, 7491M Wired, 118M Cache, 17M Buf, 51M Free
>>> ARC: 5112M Total, 1455M MFU, 2155M MRU, 7761K Anon, 293M Header, 1223M
>>> Other
>>> Swap: 2045M Total, 757M Used, 1287M Free, 37% Inuse, 1280K Out
>>
>> Just a +1 from me:
>>
>> Mem: 1440M Active, 412M Inact, 5889M Wired, 82M Cache, 90M Free
>> ARC: 3990M Total, 1981M MFU, 1505M MRU, 533K Anon, 79M Header, 424M Other
>> Swap: 8192M Total, 1434M Used, 6758M Free, 17% Inuse
>>
>> This machine is up for 1+03:13:06
>>
>
> Guys,
>
> could you please set sysctl vm.lowmem_period to zero (after a fresh reboot) and
> see if it makes any difference?

Ok, there are some results:

It starts with ARC at ~4G. Probably I should've taken some snapshots but 
I was waiting for at least one day of uptime. After that I started 
openoffice build in tmpfs. In something like an hour I got this:

Mem: 1167M Active, 2453M Inact, 3483M Wired, 57M Cache, 752M Free
ARC: 1060M Total, 199M MFU, 467M MRU, 6836K Anon, 31M Header, 356M Other
Swap: 8192M Total, 7218M Used, 974M Free, 88% Inuse, 36K In

As you can see ARC shrinked a lot and Inact is still big.

So I cleared some space in tmpfs and ordered VirtualBox to unthaw some 
host. Kindda risky thing as It was pretty tight on memory. The host 
needs ~1150Mb of memory.

Mem: 1806M Active, 1216M Inact, 2638M Wired, 1431M Cache, 820M Free
ARC: 1231M Total, 255M MFU, 564M MRU, 34M Anon, 32M Header, 345M Other
Swap: 8192M Total, 7065M Used, 1127M Free, 86% Inuse, 13M Out

Hey, cheater! ARC grows! you can see Inact is been swapped out.

Mem: 1871M Active, 676M Inact, 2649M Wired, 1946M Cache, 770M Free
ARC: 1226M Total, 246M MFU, 599M MRU, 4112K Anon, 32M Header, 345M Other
Swap: 8192M Total, 7623M Used, 569M Free, 93% Inuse, 14M Out

30 seconds passed - ARC is at the same level while Inact lost 600Mb.

Mem: 1918M Active, 185M Inact, 3193M Wired, 1788M Cache, 828M Free
ARC: 1405M Total, 390M MFU, 607M MRU, 30M Anon, 33M Header, 345M Other
Swap: 8192M Total, 8150M Used, 42M Free, 99% Inuse, 16K In

Restoration done. Openoffice is still building and VirtualBox host is 
running. That was close.

Mem: 993M Active, 425M Inact, 4638M Wired, 11M Cache, 1845M Free
ARC: 2081M Total, 749M MFU, 913M MRU, 797K Anon, 37M Header, 382M Other
Swap: 8192M Total, 673M Used, 7519M Free, 8% Inuse

tmpfs cleaned, host exited. ARC grows...

-- 
Sphinx of black quartz, judge my vow.