Is swap usage normal on an appliance?

Question

I've got several 5220s and when I check "top" on them I see that they are all using all available memory and are into swap.&nbsp; I will be restarting these appliances in the near future so will be able to monitor this usage more closely, but in your experiences have your appliances tended to use up all their memory and get into swap space like this?

Granted - they aren't using a whole lot of swap (4-6GB), but these systems have 96GB of memory so I'm kind of surprised that there is any swap use at all.

Details:

5220 appliances running 2.6.0.2
74TB storage (64TB MSDP)
96GB memory

&nbsp;

symterry · Answer

Hello

Please refer to&nbsp;TECH184147&nbsp;as this is expected behaviour. Are you seeing some sort of performance issue or just curious?

elanmbx · Answer

I'm familiar with this sort of behavior in Linux - the thing is, with "normal" usage of all the memory in Linux there is NO swap use. Once swap space starts getting used, there generally is some kind of issue. Especially when talking systems with 96GB of memory. If there was 0 swap use I wouldn't be concerned.

maintenance-!> free -m
             total       used       free     shared    buffers     cached
Mem:         96303      96057        245          0         18      49332
-/+ buffers/cache:      46705      49597
Swap:        66671       5259      61412
maintenance-!>

maintenance-!&gt; free -m
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; total&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; used&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; free&nbsp;&nbsp;&nbsp;&nbsp; shared&nbsp;&nbsp;&nbsp; buffers&nbsp;&nbsp;&nbsp;&nbsp; cached
Mem:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 96303&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 96057&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 245&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 18&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 49332
-/+ buffers/cache:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 46705&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 49597
Swap:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 66671&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 5259&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 61412
maintenance-!&gt;

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elanmbx · Answer

I'm familiar with this behavior in Linux - but it generally doesn't result in any swap usage.&nbsp; The swap use is my concern.

I have been noticing what seem to be slower duplications/replications as of late, and that is what led me to this discovery...

symterry · Answer

I checked with a Appliance SME and with 2.6, this is normal. If its 2.5 then soimething is going on. You may want to open a case. What version are you on?&nbsp;

elanmbx · Answer

2.6.0.2
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Is swap usage normal on an appliance?

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