Linux memory Usage
list Vaishnavi R
Hi friends,
I have installed Hobbit on Red Hat ES Linux.
Everything works fine but I feel the memory usage by Hobbit is high.
My Hobbit version is 4.1.2p1
I am not very good on Linux and am not sure how to find out which process is
consuming so much memory. The reason for my concern is especially because
the server had crashed after a week of Hobbit running continuously. There is
nothing but couple of apache web sites running on that server( Those ae also
experimental sites and dont have much activity on them)
Following is a snapshot of how memory was used
Initial
@Thu Apr 20 03:05:45 IST 2006
total used free shared buffers
cached
Mem: 2066872 1631232 435640 0 98028 1230052
-/+ buffers/cache: 303152 1763720
Swap: 8193108 160 8192948
Started Hobbit
@Thu Apr 20 03:11:08 IST 2006
total used free shared buffers cached
Mem: 2066872 1639936 426936 0 98612 1233888
-/+ buffers/cache: 307436 1759436
Swap: 8193108 160 8192948
@Thu Apr 20 03:47:42 IST 2006
total used free shared buffers cached
Mem: 2066872 1644304 422568 0 101072 1235068
-/+ buffers/cache: 308164 1758708
Swap: 8193108 160 8192948
@Thu Apr 20 09:16:34 IST 2006
total used free shared buffers cached
Mem: 2066872 1868176 198696 0 143732 1364528
-/+ buffers/cache: 359916 1706956
Swap: 8193108 160 8192948
Stopped Hobbit
total used free shared buffers cached
Mem: 2066872 1865080 201792 0 144216 1364564
-/+ buffers/cache: 356300 1710572
Swap: 8193108 160 8192948
I would be grateful for any pointers to resolving this problem.
--
Thanks and regards,
Vaishnavi R
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list Henrik Størner
▸
On Thu, Apr 20, 2006 at 07:56:27AM -0400, Vaishnavi R wrote:
I have installed Hobbit on Red Hat ES Linux. Everything works fine but I feel the memory usage by Hobbit is high. My Hobbit version is 4.1.2p1 I am not very good on Linux and am not sure how to find out which process is consuming so much memory.
[snip]
Following is a snapshot of how memory was used
The data you provide is simply not enough to say what is using your memory. A look at your data shows a couple of things: 1) Swap is just not used - it stays constant at 160 KB. So there's really no memory pressure at all. 2) The "used" column in the "-/+ buffers/cache" is what you should be looking at. Linux will use lots of memory for various types of disk caches, but these can be freed instantaneously if some application needs memory. So when evaluating your memory usage, you shouldn't really count the buffer/cache memory as "used". Memory usage grows from ~296 MB upon startup to ~300 MB after starting Hobbit - it seems quite reasonable for Hobbit to use 4 MB of memory just to run. Half an hour later, it's grown an extra MB, which is also normal as more data is being recorded by Hobbit. After that it should be stable, unless you add more tests or hosts, of course. 6 hours later you're up to 350 MB used - whether that is used by Hobbit or something else I cannot tell. What you *really* should do is to see how much memory the different processes are using. E.g. $ ps vax --sort -rss will show a list of all processes currently running, sorted by memory usage. That should give you a much better clue at what is using memory on your system. I am fairly confident that you'll see Hobbit is not using a lot of memory. If I run this on my main production system (which is also running 4.1.2p1, incidentally), I get this: $ ps v --sort -rss -u hobbit PID TTY STAT TIME MAJFL TRS DRS RSS %MEM COMMAND 745 ? S 1780:29 1 162 27077 25600 2.4 hobbitd --pidfile 1241 ? S 918:42 1 154 11789 10008 0.9 hobbitd_alert --c 1242 ? S 2638:33 7 167 6696 2984 0.2 hobbitd_rrd --rrdd 27775 ? S 153:39 1 146 4341 2704 0.2 hobbitd_client 27774 ? S 63:42 0 99 2844 1832 0.1 hobbitd_channel -- 6171 ? S 338:33 1 167 5624 1736 0.1 hobbitd_rrd --rrdd 6582 ? S 0:00 0 669 2002 1344 0.1 sh -c vmstat 300 2 1234 ? S 3099:30 1 99 2332 1264 0.1 hobbitd_channel -- 1233 ? S 629:37 1 99 2332 1200 0.1 hobbitd_channel -- 1232 ? S 12:41 1 99 2332 1184 0.1 hobbitd_channel -- 6170 ? S 153:12 0 99 2332 1144 0.1 hobbitd_channel -- 1243 ? S 21:55 0 108 2515 1136 0.1 hobbitd_history 6584 ? S 0:00 0 79 1824 760 0.0 vmstat 300 2 743 ? Ss 1:06 0 101 1802 696 0.0 hobbitlaunch --con This system has 1 GB of memory, and handles over 2000 monitored hosts. It's been running since March 12. And Hobbit uses 52 MB of memory (sum of the RSS column, where numbers are in KB). Regards, Henrik
list Vaishnavi R
Hello, Thanks so much for the prompt response. I tried $ ps vax --sort -rss and Hobbit is not at the top. I shall be montiroing for a day just to be sure. Thanks again. Regards, Vaishnavi
▸
On 4/20/06, Henrik Stoerner <user-ce4a2c883f75@xymon.invalid> wrote:On Thu, Apr 20, 2006 at 07:56:27AM -0400, Vaishnavi R wrote:I have installed Hobbit on Red Hat ES Linux. Everything works fine but I feel the memory usage by Hobbit is high. My Hobbit version is 4.1.2p1 I am not very good on Linux and am not sure how to find out which process is consuming so much memory.[snip]Following is a snapshot of how memory was usedThe data you provide is simply not enough to say what is using your memory. A look at your data shows a couple of things: 1) Swap is just not used - it stays constant at 160 KB. So there's really no memory pressure at all. 2) The "used" column in the "-/+ buffers/cache" is what you should be looking at. Linux will use lots of memory for various types of disk caches, but these can be freed instantaneously if some application needs memory. So when evaluating your memory usage, you shouldn't really count the buffer/cache memory as "used". Memory usage grows from ~296 MB upon startup to ~300 MB after starting Hobbit - it seems quite reasonable for Hobbit to use 4 MB of memory just to run. Half an hour later, it's grown an extra MB, which is also normal as more data is being recorded by Hobbit. After that it should be stable, unless you add more tests or hosts, of course. 6 hours later you're up to 350 MB used - whether that is used by Hobbit or something else I cannot tell. What you *really* should do is to see how much memory the different processes are using. E.g. $ ps vax --sort -rss will show a list of all processes currently running, sorted by memory usage. That should give you a much better clue at what is using memory on your system. I am fairly confident that you'll see Hobbit is not using a lot of memory. If I run this on my main production system (which is also running 4.1.2p1, incidentally), I get this: $ ps v --sort -rss -u hobbit PID TTY STAT TIME MAJFL TRS DRS RSS %MEM COMMAND 745 ? S 1780:29 1 162 27077 25600 2.4 hobbitd --pidfile 1241 ? S 918:42 1 154 11789 10008 0.9 hobbitd_alert --c 1242 ? S 2638:33 7 167 6696 2984 0.2 hobbitd_rrd --rrdd 27775 ? S 153:39 1 146 4341 2704 0.2 hobbitd_client 27774 ? S 63:42 0 99 2844 1832 0.1 hobbitd_channel -- 6171 ? S 338:33 1 167 5624 1736 0.1 hobbitd_rrd --rrdd 6582 ? S 0:00 0 669 2002 1344 0.1 sh -c vmstat 300 2 1234 ? S 3099:30 1 99 2332 1264 0.1 hobbitd_channel -- 1233 ? S 629:37 1 99 2332 1200 0.1 hobbitd_channel -- 1232 ? S 12:41 1 99 2332 1184 0.1 hobbitd_channel -- 6170 ? S 153:12 0 99 2332 1144 0.1 hobbitd_channel -- 1243 ? S 21:55 0 108 2515 1136 0.1 hobbitd_history 6584 ? S 0:00 0 79 1824 760 0.0 vmstat 300 2 743 ? Ss 1:06 0 101 1802 696 0.0 hobbitlaunch --con This system has 1 GB of memory, and handles over 2000 monitored hosts. It's been running since March 12. And Hobbit uses 52 MB of memory (sum of the RSS column, where numbers are in KB). Regards, Henrik
-- Vaishnavi R ======================================================== This message contains information that may be privileged or confidential and is the property of Opus Software Solutions Group. It is intended only for the person to whom it is addressed. If you are not the intended recipient, you are not authorized to read, print, retain, copy, disseminate, distribute, or use this message or any part thereof. If you receive this message in error, please notify the sender immediately and delete all copies of this message
list Taylor Lewick
When I pull up hobbit graphs for memory for one of our database servers with 16 GB of memory, I see the Actual Memory Used is reporting as 657 M and swap is 0 M Used. But if I run ps -vax --sort -rss note the top 4 processes... Looks like just over 7.0 GB of memory is consumed. I'm deleting PID, TTY and STAT colum to make sure it all fits on one line. TIME MAJFL TRS DRS RSS %MEM COMMAND 12:39 4 3519 3310360 3193428 19.4 postgres: 4:22 0 3519 3312708 3077228 18.7 postgres: 0:31 0 3519 3312832 993816 6.0 postgres: 0:26 0 3519 3312128 192740 1.1 postgres: Output of free shows... total used free shared buffers cached Mem: 16433348 16252424 180924 0 168500 15409800 -/+ buffers/cache: 674124 15759224 Swap: 8355832 540 8355292 So is the system telling me that most of the memory the processes are taking up from the ps -vax output is cached and can be released at any time? Thanks,
list Dominique Frise
▸
Taylor Lewick wrote:
When I pull up hobbit graphs for memory for one of our database servers with 16 GB of memory, I see the Actual Memory Used is reporting as 657 M and swap is 0 M Used. But if I run ps -vax --sort -rss note the top 4 processes... Looks like just over 7.0 GB of memory is consumed. I'm deleting PID, TTY and STAT colum to make sure it all fits on one line. TIME MAJFL TRS DRS RSS %MEM COMMAND 12:39 4 3519 3310360 3193428 19.4 postgres: 4:22 0 3519 3312708 3077228 18.7 postgres: 0:31 0 3519 3312832 993816 6.0 postgres: 0:26 0 3519 3312128 192740 1.1 postgres: Output of free shows... total used free shared buffers cached Mem: 16433348 16252424 180924 0 168500 15409800 -/+ buffers/cache: 674124 15759224 Swap: 8355832 540 8355292 So is the system telling me that most of the memory the processes are taking up from the ps -vax output is cached and can be released at any time?
That is also what I understand. "Actual" shows memory that cannot be released. This value is the one to watch. Dominique