Sponsored Content
Special Forums Hardware Filesystems, Disks and Memory Poor read performance on sun storedge a1000 Post 302302357 by TonyFullerMalv on Monday 30th of March 2009 07:00:29 PM
Old 03-30-2009
If a raid 10 made up of 12 disks is 6 disks in a striped volume mirrored against another volume of 6 disks in a striped volume, the the mirroring process (which has to write to both striped volumes) slows down writes compared with reading (which only has to read from one of the striped volumes), normally.

I think writing to /dev/zero is not a good idea, I would try writing to /dev/null instead.

Reading from /dev/random would be interesting to compare with reading from /dev/zero also?
 

9 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

veritas/STOREDGE A1000

Hi, I am a Dba and very new to filesystems and stuff. I think that we have Veritas filesystems on my Sun SOlaris 5.8 box, how do I confirm this: all my filesystems are mounted like this: /dev/vx/dsk... Now we are also using disk arrays (storedge a1000) how do I access them from the system.... (1 Reply)
Discussion started by: knarayan
1 Replies

2. UNIX for Advanced & Expert Users

Samba on E3500 Poor Performance!!!

Hi you all, I have a BIG performance problem on an Sun E3500, the scenario is described below: I have several users (30) accessing via samba to the E3500 using an application built on Visual Foxpro from their Windows PC , the problem is that the first guy that logs in demands 30% of the E3500... (2 Replies)
Discussion started by: alex blanco
2 Replies

3. UNIX for Advanced & Expert Users

Storedge A1000 Controller Firmware question

Hello everyone. I'm trying to setup two A1000s connected to a single host w/ a dual port adapter. The host is a V480. Do I need to have thesame firmware version on both controllers for the A1000s? If so, where can I download the latest and greatest firmware? I tried to google for it and... (8 Replies)
Discussion started by: xnightcrawl
8 Replies

4. UNIX for Advanced & Expert Users

Help: Sun Disk partitioning for Sun V240 & StorEdge 3300

Dear Sun gurus, I have Sun Fire V240 server with its StorEdge 3300 disk-array. Following are its disks appeared in format command. I have prepared its partitions thru format and metainit & metattach (may be i have made wrong steps, causing the errors below because I have done thru some document... (1 Reply)
Discussion started by: shafeeq
1 Replies

5. Solaris

How can i connect storedge A1000 to E250box?

Hello Experts, I am using E250 on that solais 10 5/08 installed. I am unable to see disks. I connected 2 disks in that storage of 18gb each. When I run format command it is showing that 2 disks one is operating system and another one is 6MB. I checked probe-scsi and probe-scsi-all at ok... (6 Replies)
Discussion started by: younus_syed
6 Replies

6. UNIX for Advanced & Expert Users

HW Raid poor io performance

Hello all We just built a storage cluster for our new xenserver farm. Using 3ware 9650SE raid controllers with 8 x 1TB WD sata disks in a raid 5, 256KB stripe size. While making first performance test on the local storage server using dd (which simulates the read/write access to the disk... (1 Reply)
Discussion started by: roli8200
1 Replies

7. Solaris

Poor Disk performance on ZFS

Hello, we have a machine with Solaris Express 11, 2 LSI 9211 8i SAS 2 controllers (multipath to disks), multiport backplane, 16 Seagate Cheetah 15K RPM disks. Each disk has a sequential performance of 220/230 MB/s and in fact if I do a dd if=/dev/zero of=/dev/rdsk/<diskID_1> bs=1024k... (1 Reply)
Discussion started by: golemico
1 Replies

8. AIX

Poor Performance of server

Hi, I am new registered user here in this UNIX forums. I am a new system administrator for AIX 6.1. One of our servers performs poorly every time our application (FINACLE) runs many processes/instances. (see below for topas snapshot) I use NMON or Topas to monitor the server utilization. I... (9 Replies)
Discussion started by: guzzelle
9 Replies

9. Solaris

Poor performance on an M3000

Hi We have an M3000 single physical processor and 8gb of memory running Solaris 10. This system runs two Oracle Databases one on Oracle 9i and One on Oracle 10g. As soon as the Oracle 10g database starts we see an immediate drop in system performance, for example opening an ssh session can... (6 Replies)
Discussion started by: gregsih
6 Replies
NASH(8) 						      System Manager's Manual							   NASH(8)

NAME
nash - script interpretor to interpret linuxrc images SYNOPSIS
nash [--quiet] [--force] script DESCRIPTION
nash is a very simple script interpretor designed to be as small as possible. It is primarily designed to run simple linuxrc scripts on an initrd image. Arguments to commands may be enclosed in either single or double quotes to allow spaces to be included in the arguments. Spa- ces outside of quotations always delineate arguments, and so backslash escaping is supported. Additionally, if nash is invoked as modprobe, it will immediately exit with a return code of zero. This is to allow initrd's to prevent some extraneous kernel error messages during startup. There are two types of commands, built in and external. External commands are run from the filesystem via execve(). If commands names are given without a path, nash will search it's builtin PATH, which is /usr/bin, /bin, /sbin, /usr/sbin. Currently, nash supports the following built in commands. access -[r][w][x][f] path Tells whether the current user has sufficient permissions to read, write, or execture path, or if the file exists (see access(2) for more information). echo [item]* [> filename] Echos the text strings given to a file, with a space in between each item. The output may be optionally redirected to a file. exec <command> The command given is execed, overlaying the nash process. find dir -name name Display the path to files named name in or below directory dir. This is a very limited implementation of find(1). findlodev Prints the full path to the first unused loopback block device on the system. If none is available, no output is displayed. losetup /dev/loopdev file Binds file to the loopback device /dev/loopdev. See losetup(8) for information on loopback devices. mkdevices path Creates device files for all of the block devices listed in /proc/partitions in the directory specfied by path. mkdir [-p] path Creates the directory path. If -p is specified, this command will not complain if the directory exists. Note this is a subset of the standard mkdir -p behavior. mknod path [c|b] major minor Creates a device inode for path. This is identical to mkdev(1) which the exceptions that it will not create named pipes and if the directories in path do not exist they will be automatically created. mkrootdev path Makes path a block inode for the device which should be mounted as root. To determine this device nash uses the device suggested by the root= kernel command line argument (if root=LABEL is used devices are probed to find one with that label). If no root= argument is available, /proc/sys/kernel/real-root-dev provides the device number. mount [--ro] -o opts -t type device mntpoint Mounts a filesystem. It does not support NFS, and it must be used in the form given above (arguments must go first). If device is of the form LABEL=foo the devices listed in /fB/proc/partitions will be searched, and the first device with a volume label of foo will be mounted. Normal mount(2) options are supported, and --ro will mount the filesystem read only for compatibility with older versions of nash. The defaults mount option is silently ignored. pivot_root newrootpath oldrootpath Makes the filesystem mounted at newrootpath the new root filesystem, and mounts the current root filesystem as oldrootpath. raidautorun mddevice Runs raid autodetection on all raid-typed partitions. mddevice must be a raid device (any will do). showlabels Display a table of devices, their filesystem labels, and their uuids. umount path Unmounts the filesystem mounted at path. RETURN VALUE
Returns 0 is the last command succeeded or 1 if it failed. OPTIONS
--force Allows force really execute the script, even though nash doesn't appear to be running from an initrd image. BUGS
Probably many. nash is not a shell, and it shouldn't be thought of as one. It isn't entirely different from a shell, but that's mostly by accident. AUTHOR
Erik Troan <ewt@redhat.com> 4th Berkeley Distribution Sat Mar 27 1999 NASH(8)
All times are GMT -4. The time now is 08:41 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy