10 More Discussions You Might Find Interesting
1. Red Hat
Hi
the version is RedHat 6.2 (Oracle DB server)
I don't know why swap memory usage keeps increasing...
I used to check swap memory usage Free -m and another way.
total used free shared buffers cached
Mem: 32183 31861 322 ... (3 Replies)
Discussion started by: tom8254
3 Replies
2. Red Hat
Hi ,
There is one following alert .
Message : cdm:Average (2 samples) swap memory usage is now 91%, which is above the warning threshold (90%)
Here is my findings.
Output of TOP command in Linux server.
top - 14:21:44 up 6 days, 4:48, 1 user, load average: 2.55, 2.06,... (3 Replies)
Discussion started by: Maddy123
3 Replies
3. Solaris
Hi
We have 2 identical T4-1's running Solaris 10 8/11 patched to 07/2012.
Both have 8G of swap allocated on the zfs root pool however a swap -s on one server shows 8G of swap available but on the other shows between 60 and 115G of swap available.
Both servers have the same amount of... (6 Replies)
Discussion started by: gregsih
6 Replies
4. Shell Programming and Scripting
Its rather confusing, the output of top command is below:
The "swap" field of top is described by the manpage as: "The swapped out portion of a task's total virtual memory image."
But the output of free command suggests something else and it does tally with the output of swapon... (3 Replies)
Discussion started by: proactiveaditya
3 Replies
5. Shell Programming and Scripting
Hi Folks,
I am looking for a way to write a script to calculate swap usage in Solaris so that the current usage will be shown in Percentage value. Thanks!!
Based on 'swap -s' command
# swap -s
total: 1378936k bytes allocated + 1236880k reserved = 2615816k used, 2725104k available (2 Replies)
Discussion started by: jaapar
2 Replies
6. Solaris
hi guys
i am new to opensolaris and i have installed opensolaris 2009.6 preview
and i would like to know how much swap using each process currently..... (6 Replies)
Discussion started by: srinivas2828
6 Replies
7. Solaris
Is there any way to get list of processes which are taking maximum swap , my system is showing no swap space in /var/adm/messages and i 'm unable to pin down the process which is consuming max swap space. (11 Replies)
Discussion started by: fugitive
11 Replies
8. HP-UX
how can I find cpu usage memory usage swap usage and
I want to know CPU usage above X% and contiue Y times and memory usage above X % and contiue Y times
my final destination is monitor process
logical volume usage above X % and number of Logical voluage above
can I not to... (3 Replies)
Discussion started by: alert0919
3 Replies
9. UNIX for Dummies Questions & Answers
Trying to come up with a command that will show all processes sorted from highest cpu usage to lowest. Any ideas? (9 Replies)
Discussion started by: cwsmichigan
9 Replies
10. Shell Programming and Scripting
Hi,
How do i get the swap space used and cpu usage for a particular application ?
thanks
una (2 Replies)
Discussion started by: una
2 Replies
swchunk(5) File Formats Manual swchunk(5)
NAME
swchunk - swap chunk size in 1 KB blocks
VALUES
Default
Allowed values
blocks
blocks
DESCRIPTION
Swap space in the kernel is managed using 'chunks' of physical device space. These chunks contain one or more (usually more) pages of mem-
ory, but provide another layer of indexing (similar to inodes in file systems) to keep the global swap table relatively small, as opposed
to a large table indexed by swap page.
controls the size in physical disk blocks (which are defined as 1 KB) for each chunk. The total bytes of swap space manageable by the sys-
tem is * 1 KB * 2,147,483,648 (the system maximum number of swap chunks in the swap table). Note that the minimum (or default) value of
therefore allows 4,096 TB of swap space.
The way to think of is not as the size of the I/O transactions in the swap system (in disk blocks), but as the number of blocks that will
be placed on one swap device (or file system) before moving to the next device (assuming all priorities are equal). This spreads the swap
space over any devices and is called swap interleaving. Swap interleaving spreads out the swap over many devices and reduces the possibil-
ity of one single device becoming a bottleneck for the entire system when swap usage is heavy.
Who is Expected to Change This Tunable?
This tunable should only be modified by those with a complete knowledge of both kernel behavior and underlying device hardware.
Restrictions on Changing
Changes to this tunable take effect at the next reboot.
When Should the Value of This Tunable Be Raised?
If the system owner wishes to add more swap to the system, but the additional swap chunks needed are unavailable, raising this tunable will
work around the problem. By increasing the size of each chunk, fewer total chunks are needed.
What Are the Side Effects of Raising the Value?
The second level of the swap table (used to track pages within a chunk) will increase, resulting in more memory used by the kernel. If is
being increased to allow for mapping of a larger swap space, increased memory usage by the kernel to track the swap space is unavoidable.
This means that more swap is allocated to each device (or file system) using the round-robin interleaving scheme when all priorities are
equal. Increasing when the number of chunks needed to represent the system swap space is less than 2,147,483,648 could hinder system per-
formance by creating unneeded I/O bottlenecks. For example, two pages that were in different chunks using the smaller value which were
previously on different swap devices and thus accessible independently of one another (with no read head or controller issues) are now on
the same device and cannot be read concurrently, resulting in a longer access time for the second page.
When Should the Value of This Tunable Be Lowered?
If the amount of swap space mappable by the system is much larger than the total amount of swap space which is attached (or going to be
attached) to the system, which is calculable by multiplying 2,147,483,648 * 1 KB, then kernel memory usage can be reduced by lowering to
fit the actual swap space.
What Are the Side Effects of Lowering the Value?
It may have to be raised back if more swap is added to the system and there is not enough room in the swap table to allow for the increased
space. If this is not the case, then there is a finer grain of interleaving on the system (assuming there is more than one swap device)
that can provide a performance gain under heavy swap usage.
What Other Tunable Values Should Be Changed at the Same Time?
A change to is independent of any other tunables.
WARNINGS
All HP-UX kernel tunable parameters are release specific. This parameter may be removed or have its meaning changed in future releases of
HP-UX.
Installation of optional kernel software, from HP or other vendors, may cause changes to tunable parameter values. After installation,
some tunable parameters may no longer be at the default or recommended values. For information about the effects of installation on tun-
able values, consult the documentation for the kernel software being installed. For information about optional kernel software that was
factory installed on your system, see at
AUTHOR
was developed by HP.
Tunable Kernel Parameters swchunk(5)