1) I can confirm that the system is AIX -
2) The file system is mount (called lv_test_3)
Good. Sorry for sometimes stating the obvious superfluously, the general experience of long-standing members here is that the painfully obvious is less obvious one might think to the better part of the audience.
Quote:
Originally Posted by tugger
3) I am aware all the dd process will run in parallel as that is the aim to look into the throughput on the LVM (SAN attached disks) and the benefit (if any) of having the inter policy set to maximum
If you are carrying out performance tests you might consider taking the file system driver out of the equation by addressing the raw device instead of the filesystem:
or even the raw hard disk. I once did exactly that for the same reasons, you can read here an account of the risks involved - afterwards it was quite funny.
Quote:
Originally Posted by tugger
Therefore your theory of the bs being held in memory might be correct.
I was trying a bs of 512m with the thought that it might be faster than using a bs of 1m.
Give the LPAR more memory, then (6GB should suffice). Increase not the "max" alone in the profile, increase the "Desired" too. Fork()-ing 10 such processes will be done faster than the hypervisor can react.
This is my first post, and I am new to the UNIX world. Hopefully this question won't be too lame.
I know that I can use topas to see the paging space used by some processes. I would like to script something that can add up the paging space used by process owned by or associated with an... (1 Reply)
Greetings
I have an older box (H50) that has it's paging space setup the following way:
$ lsps -a
Page Space Physical Volume Volume Group Size %Used Active Auto Type
paging00 hdisk0 rootvg 224MB 1 yes yes lv
hd6 hdisk0 ... (4 Replies)
Hello, we have a problem with lpar with AIX 5.3, the issue is that has high level paging space with: _sqlsrv2 and its incremented continously (1 Reply)
sorry for this silly question, I am new to UNIX,
what is meant by paging space and what is its purpose?
what is also meant by hd6 paging space? (2 Replies)
Hello everyone
I have 4g of paging space in my rootvg disk
I´m going to reduce them to 1gb in my rootvg disk and add 3gb of paging space on my san disk.
My rootvg disk is mirror.
My question is I can do this on line ?
and I can do with the mirror ? or I need to unmirror first my... (2 Replies)
Hi
I have used gzip on AIX and the used paging space has jumped from 7% to 20%. The gzip process is finished since a long time. But the used paging space is still the same. How to release this space ? (1 Reply)
Hello everyone
I have a doubt about how many paging space can have in the same disk.
lsps -a
Page Space Physical Volume Volume Group Size %Used Active Auto Type
paging00 hdisk0 rootvg 3072MB 1 yes yes lv
hd6 hdisk0 ... (4 Replies)
Hello dear friends, We have VG filevg which consists of 2 PVs when I rechecked the VG there is no Pagingspace LV.. The VG is usually Highly loaded because much reads and writes.. Is this a must to create Paging space on the specified LV? (2 Replies)
Hi,
I have paging size 2048M showed from topas and 10240M showed from "lsps -a", can anyone tell what is the difference? and how to change the PAGING SIZE (showed in topas) to 8192M?
Can you please tell in detail step?
Thanks!
Victor
#topas
Topas Monitor for host: egsprc01dev ... (10 Replies)
Discussion started by: victorcheung
10 Replies
LEARN ABOUT REDHAT
raw
RAW(8) System Manager's Manual RAW(8)NAME
raw - bind a Linux raw character device
SYNOPSIS
raw /dev/raw/raw<N> <major> <minor>
raw /dev/raw/raw<N> /dev/<blockdev>
raw -q /dev/raw/raw<N>
raw -qa
DESCRIPTION
raw is used to bind a Linux raw character device to a block device. Any block device may be used: at the time of binding, the device
driver does not even have to be accessible (it may be loaded on demand as a kernel module later).
raw is used in two modes: it either sets raw device bindings, or it queries existing bindings. When setting a raw device, /dev/raw/raw<N>
is the device name of an existing raw device node in the filesystem. The block device to which it is to be bound can be specified either
in terms of its major and minor device numbers, or as a path name /dev/<blockdev> to an existing block device file.
The bindings already in existence can be queried with the -q option, with is used either with a raw device filename to query that one
device, or with the -a option to query all bound raw devices.
Once bound to a block device, a raw device can be opened, read and written, just like the block device it is bound to. However, the raw
device does not behave exactly like the block device. In particular, access to the raw device bypasses the kernel's block buffer cache
entirely: all I/O is done directly to and from the address space of the process performing the I/O. If the underlying block device driver
can support DMA, then no data copying at all is required to complete the I/O.
Because raw I/O involves direct hardware access to a process's memory, a few extra restrictions must be observed. All I/Os must be cor-
rectly aligned in memory and on disk: they must start at a sector offset on disk, they must be an exact number of sectors long, and the
data buffer in virtual memory must also be aligned to a multiple of the sector size. The sector size is 512 bytes for most devices.
Use the /etc/sysconfig/rawdevices file to define the set of raw device mappings automatically created during the system startup sequence.
The format of the file is the same used in the command line with the exception that the "raw" command itself is omitted.
OPTIONS -q Set query mode. raw will query an existing binding instead of setting a new one.
-a With -q , specifies that all bound raw devices should be queried.
-h provides a usage summary.
BUGS
The Linux dd (1) command does not currently align its buffers correctly, and so cannot be used on raw devices.
Raw I/O devices do not maintain cache coherency with the Linux block device buffer cache. If you use raw I/O to overwrite data already in
the buffer cache, the buffer cache will no longer correspond to the contents of the actual storage device underneath. This is deliberate,
but is regarded either a bug or a feature depending on who you ask!
AUTHOR
Stephen Tweedie (sct@redhat.com)
Version 0.1 Aug 1999 RAW(8)