From: Örjan Petersson (orjan.petersson@logcode.com)
Date: Wed Jan 12 2005 - 17:12:14 EST
Hi,
I have a few questions on the memory usage on our servers, 2 clustered 4 CPU ES80 with
8 GB RAM running Tru64 5.1B. The cluster is running a telecom billing system in
failover mode. Everything runs on one machine and the other just hangs around doing
basically nothing. The system is based around an Oracle 8.1.7 database with a 2 GB SGA.
The sum of the RSS of all running processes is 2-3 GB.
Q1: vmstat on the standby machine indicates roughly 275 page faults/s even though
the machine is idle most of its time. What can be the explanation for that?
eppix@eppix01> vmstat 1
Virtual Memory Statistics: (pagesize = 8192)
procs memory pages intr cpu
r w u act free wire fault cow zero react pin pout in sy cs us sy id
6 329 185 39K 902K 71K 27M 2M 18M 0 4M 0 4K 990 7K 0 5 95
7 332 185 39K 902K 71K 243 40 210 0 71 0 3K 509 8K 0 4 95
6 329 185 39K 902K 71K 36 25 183 0 43 0 3K 333 7K 0 8 92
7 329 184 39K 902K 71K 277 25 183 0 43 0 3K 491 7K 0 2 98
6 329 185 39K 902K 71K 277 0 0 0 0 0 3K 492 6K 0 1 99
Q2: On the active machine we see a very high page fault count for one of the RADs,
54G versus 360-380M for the others (The machine is up since Jan. 5). What are
the possible explanations for this? Can it have something to do with the Oracle
SGA shared memory segment that might be on that RAD? Is it possible to verify
this hypothesis?
eppix@eppix02> vmstat -R
Virtual Memory Statistics: (pagesize = 8192)
procs memory pages intr cpu
RAD r w u st sw act actv actu acti free wire wirv wiru fault cow zero react pin pout in sy cs us sy id
0 5 272 138 0 0 187K 64K 61K 61K 2320 58K 25K 0 376M 36M 217M 15M 41M 1M 405 8K 6K 34 18 48
1 4 176 17 0 0 204K 42K 71K 90K 2031 48K 22K 0 53G 46M 284M 9M 60M 740K 602M 5G 1G 27 34 39
2 4 155 20 0 0 180K 49K 65K 65K 8577 65K 22K 0 380M 33M 213M 8M 40M 843K 263M 5G 2G 32 16 52
3 4 263 21 0 0 185K 49K 34K 101K 2019 67K 17K 0 367M 35M 195M 7M 42M 678K 229K 4G 2G 31 15 54
-- 17 866 196 0 0 758K 205K 232K 319K 14K 239K 87K 0 54G 151M 909M 40M 185M 3M 1G 20G 11G 31 21 48
Q3: (Related to Q1?) I do not have the impression that we are short on memory but
on the active machine we have a couple of thousand page faults/s. Any ideas? Can
it have something to do with the ES80 being a NUMA?
eppix@eppix02> vmstat 1
Virtual Memory Statistics: (pagesize = 8192)
procs memory pages intr cpu
r w u act free wire fault cow zero react pin pout in sy cs us sy id
27 853 194 764K 12K 235K 54G 151M 910M 40M 185M 3M 1K 32K 18K 31 21 48
19 871 197 767K 9447 236K 8352 387 2982 0 144 0 5K 45K 19K 41 43 16
22 875 195 768K 7389 236K 6430 795 4347 0 677 0 6K 51K 23K 44 41 15
18 873 197 764K 12K 236K 3241 690 5266 0 423 0 10K 75K 31K 46 38 16
21 872 195 765K 10K 236K 2300 143 2544 0 234 0 11K 71K 30K 60 36 4
27 867 194 767K 9366 236K 4620 285 3802 0 119 0 11K 62K 24K 60 34 6
-- Best regards, Örjan Petersson, Logcode SARL, currently with Ericsson Algeria 24 bis, rue Voltaire, FR-42270 St-Priest-en-Jarez, France Phone: +33-4.77.79.65.14, Mobile: +33-6.62.25.37.94, In Algeria: +213-61.699.745 -- Örjan Petersson, Logcode SARL
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