Not sure whether I would call that high. It is a 5G box afterall.

It is always hard to figure out memory related issues based on one output.
Call Oracle support. They will give you an oswatcher script that
monitors various stats giving us a much better view into the running
system.

Alexei_Roudnev wrote:
Suni, you do know it much better - is not is strange a little? (so many ext3 inode chache objects, togetrher with 3 GB of cached disk space). But I dont see anything wrong below - big 'cached' memory means only 'you have so many unused memory that system cached files in it' and nothing more. Cached memory is in reality _free for immediate use_ memory (can be used by anyone immediately). What ysstem is doing is _instead of freeing memory and filling it by zerous, free unused memory and fill it in by buffer cache data, so that if someone need these data he have them at once. If someone need more memory, system reuse any of 'chached' memory without any delay (because these are buffers which are already written to the disk or which was never udpated).
Big 'cached' value means only _big free memory_.

    ----- O riginal Message -----
    *From:* Luis Freitas <mailto:[EMAIL PROTECTED]>
    *To:* Alexei_Roudnev <mailto:[EMAIL PROTECTED]> ;
    Brian Sieler <mailto:[EMAIL PROTECTED]> ;
    [email protected] <mailto:[email protected]>
    *Sent:* Monday, April 09, 2007 4:32 PM
    *Subject:* Re: [Ocfs2-users] High on buffers and deep on swap

    Alexei,
    How can I relate the information on slabtop to the actual memory
    used by buffers?
    I see this on slabtop:
    Active / Total Objects (% used) : 603822 / 649643 (92.9%)
    Active / Total Slabs (% used) : 47216 / 47216 (100.0%)
    Active / Total Caches (% used) : 97 / 133 (72.9%)
    Active / Total Size (% used) : 176601.08K / 181508.49K (97.3%)
    Minimum / Average / Maximum Object : 0.01K / 0.28K / 128.00K
    OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME
    202461 202451 99% 0.54K 28923 7 115692K ext3_inode_cache
    232206 232153 99% 0.15K 8931 26 35724K dentry_cache
    29974 26092 87% 0.27K 2141 14 8564K radix_tree_node
    68250 62400 91% 0.05K 910 75 3640K buffer_head
    855 855 100% 4.00K 855 1 3420K pmd
    647 647 100% 4.00K 647 1 2588K size-4096
    8595 7694 89% 0.25K 573 15 2292K filp
    20835 17331 83% 0.09K 463 45 1852K vm_area_struct
    780 767 98% 2.00K 390 2 1560K size-2048
    18849 7962 42% 0.06K 309 61 1236K size-64
    2440 632 25% 0.50K 305 8 1220K size-512
    2926 2889 98% 0.34K 266 11 1064K inode_cache
    256 256 100% 3.00K 128 2 1024K biovec-(256)
    600 592 98% 1.38K 120 5 960K task_struct
    515 512 99% 1.38K 103 5 824K pirpIo
    5084 2365 46% 0.12K 164 31 656K size-128
    The largest area is about 100Mb, but on free there are over 3Gb on
    the "cached" column:
    [EMAIL PROTECTED] ~]$ free
    total used free shared buffers cached
    Mem: 5190736 4461420 729316 0 141836 3265464
    -/+ buffers/cache: 1054120 4136616
    Swap: 2048248 0 2048248
    [EMAIL PROTECTED] ~]$
    Regards,
    Luis


    */Alexei_Roudnev <[EMAIL PROTECTED]>/* wrote:

        Did you run slabtop ? It can show unreleased buffers in the
        system.

            ----- Original Message -----
            *From:* Luis Freitas <mailto:[EMAIL PROTECTED]>
            *To:* Alexei_Roudnev
            <mailto:[EMAIL PROTECTED]> ; Brian Sieler
            <mailto:[EMAIL PROTECTED]> ; [email protected]
            <mailto:[email protected]>
            *Sent:* Monday, April 09, 2007 2:29 PM
            *Subject:* Re: [Ocfs2-users] High on buffers and deep on swap

            Alexei,
            Yes, it seems to have no effect, which too is very
            strange. On 2.4 vm.freepages had a very easy to notice effect.
            There are other people having problems with buffers not
            being released on the list and some of them are forcing
            the kernel cache to be flushed with:
            echo 3 > /proc/sys/vm/drop_caches
            But I dont see this parameter on RHAS 4.0.
            Also, to be fair this seems to be a generic VM issue, I
            see this on servers that are not running ocfs2 too. And I
            only see this behavior on machines with more than 2Gb of
            memory.
            Regards,
            Luis
            Regards,
            Luis

            */Alexei_Roudnev <[EMAIL PROTECTED]>/* wrote:

                Did you tried vm.swappiness parameter?
                (/proc/sys/vm/swappiness)

                    -----
                    Original Message -----
                    *From:* Brian Sieler <mailto:[EMAIL PROTECTED]>
                    *To:* 'Luis Freitas' <mailto:[EMAIL PROTECTED]>
                    ; [email protected]
                    <mailto:[email protected]>
                    *Sent:* Sunday, April 08, 2007 10:52 PM
                    *Subject:* RE: [Ocfs2-users] High on buffers and
                    deep on swap

                    Luis, yes I am experiencing what appears to be a
                    similar problem you are describing. See my post
                    from just a few minutes ago on another thread.
                    I run a 2-node cluster with OCFS2/RAC on
                    2.6.9-34.0.2.ELsmp (RHEL 4.0) as well.
                    total used free shared buffers cached
                    Mem: 4044496 4005516 38980 0 34108 2236636
                    -/+ buffers/cache: 1734772 2309724
                    Swap: 2097144 648244 1448900
                    If you’ve uncovered anything since posting this
                    message, please pass it along?
                    
------------------------------------------------------------------------
                    *From:* [EMAIL PROTECTED]
                    [mailto:[EMAIL PROTECTED] *On
                    Behalf Of *Luis Freitas
                    *Sent:* Friday, February 23, 2007 5:32 PM
                    *To:* [email protected]
                    *Subject:* [Ocfs2-users] High on buffers and deep
                    on swap
                    Hi,
                    This is a bit off topic, hope there is not a problem.
                    Anyone out there experiencing high swapping with
                    the kernel retaining a large amount of buffers?
                    This used to be a problem on 2.4, and I usually
                    changed /proc/sys/vm/freepages to fix it. But on
                    2.6 this parameter no longer exists.
                    One of the servers here is holding over 3.5Gb of
                    cache even when using over 700Mb of swap, and free
                    memory is always low.
                    [EMAIL PROTECTED] ~]$ free
                    total used free shared buffers cached
                    Mem: 5190736 4810880 379856 0 143032 3583868
                    -/+ buffers/cache: 1083980 4106756
                    Swap: 2048248 723064 1325184
                    [EMAIL PROTECTED] ~]$
                    I am tuning /proc/sys/vm/swappiness, but this
                    seems to have no effect at all. Changed from 60 to
                    10 and seems to have no effect. The server runs
                    Oracle RAC with OCFS2.
                    Regards,
                    Luis
                    
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