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BuyVM, 2.6.32 kernel and memory usage
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BuyVM, 2.6.32 kernel and memory usage

TigersWayTigersWay Member
edited February 2012 in Help

Better to start a new thread, but still looking how to interpret these results

@dmmcintyre3 said: @TigersWay Both OpenVZ? If so, it's because BuyVM is using the 2.6.32.xx kernel on some nodes with proper usage based memory limits instead of allocation based limits.

Yes, both OpenVZ, both with 2.6.32 kernel, and both exactly the same lemp stack (classic xinetd+dropbear, nginx, mysql with myisam only, php5-fpm)....

And for the same idea (I guess), free gives me

  • BuyVM
             total       used       free     shared    buffers     cached
Mem:           512         42        469          0          0         21
-/+ buffers/cache:         20        491
Swap:            0          0          0
  • Hostigation (or any other for that matter)
             total       used       free     shared    buffers     cached
Mem:           512         76        435          0          0          0
-/+ buffers/cache:         76        435
Swap:            0          0          0

Any idea how to clearly detect this 'new memory style allocation'? And how to interpret the totals: 42+20=62 vs 76?

Comments

  • sleddogsleddog Member
    edited February 2012

    @TigersWay said: Any idea how to clearly detect this 'new memory style allocation'? And how to interpret the totals: 42+20=62 vs 76?

    It's the same principle as a dedicated box, or Xen, or KVM.

                 total       used       free     shared    buffers     cached
    Mem:           512         42        469          0          0         21
    -/+ buffers/cache:         20        491

    There's 42MB in use, of which 21MB is used by caching. So excluding cached memory there's 20MB used. 1MB is missed in the accounting owing to how bash does rounding. Regards to how to detect it, just look for non-zero values in buffers or cached.

  • FranciscoFrancisco Top Host, Host Rep, Veteran

    .18 kernels allocate based on what the processes VIRTUAL size is, not the actual RAM usage. The .32 kernel allocates users RAM based on RES, which means that things like java and such aren't garbage on OVZ anymore ;)

    Francisco

    Thanked by 1ztec
  • @Francisco said: .18 kernels allocate based on what the processes VIRTUAL size is, not the actual RAM usage. The .32 kernel allocates users RAM based on RES

    .32 kernel + some specific setup, I guess, as all my boxes don't react the same way.

  • FranciscoFrancisco Top Host, Host Rep, Veteran

    Some boxes we got are on .32, some are still on .18 since they didn't like .32 and were crashy. It's quite an annoying thing to try to debug but we're hopeful that the kernel node14 is on addresses the issues we've seen.

    Time will tell :)
    Francisco

  • @TigersWay said: Yes, both OpenVZ, both with 2.6.32 kernel

    The only boxes running 2.6.32 and openvz are the backup nodes, so unless you are running replication on that mysql install, make it go away.

  • @miTgiB said: The only boxes running 2.6.32 and openvz are the backup nodes, so unless you are running replication on that mysql install, make it go away.

    I have obviously a lot to learn, no doubt on that :-) But how am I supposed to understand this?

    # uname -r
    2.6.32-274.7.1.el5.028stab095.1
  • dmmcintyre3dmmcintyre3 Member
    edited February 2012

    @TigersWay said: I have obviously a lot to learn, no doubt on that :-) But how am I supposed to understand this?

    My standard hostigation ovz with centos 5 says:

     # uname -r 
    2.6.18-274.7.1.el5.028stab095.1

    my backup vps at hostigation says:

    # uname -r 
    2.6.32-042stab044.11

    Some templates seem to spoof a 2.6.32 kernel on 2.6.18 nodes, and the template you are using must be one of them. (one time deb 6 said .32 on BuyVM, and when I reloaded with centos it went back to .18)

    Thanked by 1TigersWay
  • I told you in the other thread =P The Hostigation is 2.6.18

    When you install specific distros they get a fake message with 2.6.32 or whatever, but it still says "el5" or enterprise linux 5, or RHEL5/Centos 5 = 2.6.18

    Thanked by 1TigersWay
  • @dmmcintyre3, @yomero Thanks! Simple and effective, I now understand :-)

  • @TigersWay said: I now understand

    That would also explain the memory differences as well, which is cool, I can now stop scratching my head.

  • @miTgiB said: I can now stop scratching my head.

    Sorry for your head :-)

  • @Francisco said: .18 kernels allocate based on what the processes VIRTUAL size is, not the actual RAM usage. The .32 kernel allocates users RAM based on RES, which means that things like java and such aren't garbage on OVZ anymore ;)

    I wonder if the changes are too big to backport the changes you describes to .18

    Is 2.6.32 stable even if swap is for the host only (or can you not control that)?

  • Now Tim is bald u_u

  • @yomero said: Tim is bald

    That is baldyric's domain

    Thanked by 1dmmcintyre3
  • @miTgiB said: That is baldyric's domain

    I'll admit, it's tempting. Shaving my head would put an end to regular haircuts, at least.

  • @Aldryic said: Shaving my head

    Be a lot cooler in the summer for sure, save on shampoo, dry faster .... Looks like a lot of advantages, yet I have no desire.

  • @Aldryic said: Shaving my head would put an end to regular haircuts, at least.

    Still gotta shave it every few days!

  • FranciscoFrancisco Top Host, Host Rep, Veteran

    @Kairus said: I wonder if the changes are too big to backport the changes you describes to .18

    Is 2.6.32 stable even if swap is for the host only (or can you not control that)?

    It's a complete redo of their whole memory system and about as stable as a woman on the rag. Some of our nodes love it, run it great, and so we've seen no issues with them. Others aren't as lucky and some crashed within hours.

    The latest 49 kernel went on node14 which has been a bit derpy on the last .32 kernels. If 14 dives on this one it's going back on an .18.

    Francisco

  • @Kairus said: Still gotta shave it every few days!

    Simpler than hassling myself to visit the barber.

  • FranciscoFrancisco Top Host, Host Rep, Veteran

    @Aldryic said: Simpler than hassling myself to visit the barber.

    Would make the hitler 'tash a little odd though.

    Francisco

  • @Francisco said: Would make the hitler 'tash a little odd though.

    New head of HR made me shave it off =\

  • FranciscoFrancisco Top Host, Host Rep, Veteran

    @Aldryic said: New head of HR made me shave it off =\

    Sounds like they thought you were trying to imitate them.

    :3

    Francisco

  • @Aldryic said: head of HR

    What type of frequent flier rewards does this place offer?

  • @miTgiB said: What type of frequent flier rewards does this place offer?

    Having to deal with my antics :P

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