That will be inaccurate because of cache... stuff written to disk just gets shoved into memory until the disk's ready. 30 gigs would probably fill the cache, but still, there's better ways that don't involve waiting for 30 gigs of data to be written.
Linux usually has the hdparm command. It has read tests that take just a few seconds:
Code:
hdparm -tT /dev/sda
/dev/sda:
Timing cached reads: 1582 MB in 2.00 seconds = 791.21 MB/sec
Timing buffered disk reads: 184 MB in 3.04 seconds = 60.61 MB/sec
There's no equivalent write-speed test but, for a traditional hard disk, read speed and write speed should be about the same.
If a file size increases in Linux/UNIX to say in GB's then will there be a decrease in write speed.
I mean will it take more time to write to a large file then to a small one??
Please clarify?
Thanks in advance (2 Replies)
I analysed disk performance with blktrace and get some data:
read:
8,3 4 2141 2.882115217 3342 Q R 195732187 + 32
8,3 4 2142 2.882116411 3342 G R 195732187 + 32
8,3 4 2144 2.882117647 3342 I R 195732187 + 32
8,3 4 2145 ... (1 Reply)
Hi,
We have smb client running on two of the linux boxes and smb server on another linux system. During a backup operation which uses smb, read of a file was allowed while write to the same file was going on.Also simultaneous writes to the same file were allowed.Following are the settings in the... (1 Reply)
Would simply like to write data (no audio) to a CD/RW disk. The disk drive states CD/RW on the front but don't know for sure if the software is configured to recognize it as a writable disk. I can read/move data from the disk to the hard drive with no issue from the disk. Any help in this... (4 Replies)
I am now on Kernel 2.6.32-26
For me 16x CD write speed is okay.
I have old hardware which was able to write DVDs at 1x, back in previous linux version.
Now, I dont get speed of less than 4x.
Tested on k3b, xfburn, and brasero. But all start at bottom 4x write speed. k3b forced back to... (0 Replies)
Hi,
I went to a computer store and the salesman sold me a SATA cable and told me that all SATA cables are the same. Another salesman at a different store told me a cable rated for SATA 2, which I bought, MIGHT work as well as one rate for SATA 3 but it is not guaranteed. I decided to run a... (3 Replies)
hi all:
as we know , when usb flash disk plug in and aotu mounted , the default permission of the usb flash disk is 700. that means others have no permission . the question: how to make others have read/write permission when the aotu mounted usb flash disk pluge in ? thanks !! (0 Replies)
Hi,
We have two servers in scenario (vmsoldot01 is Oracle VM with Linux and tldtppod15 is physical Linux server). One NAS share is mounted on both servers with similar permissions and access. But READ speed is too bad on virtual in comparison to physical server.
While trying to diagnose this, I... (2 Replies)
Hello All,
I am building a real time parser for a log file in my application.
The log file is continuously written at a very fast pace and gets rolled over every 10 minutes.
I have measured the speed and observed that around 1000 lines are written to it every second, each line about 30-40... (7 Replies)
Discussion started by: cool.aquarian
7 Replies
LEARN ABOUT ULTRIX
dskx
dskx(8) System Manager's Manual dskx(8)Name
dskx - generic disk exerciser
Syntax
/usr/field/dskx [ options ] -rdev
/usr/field/dskx [ options ] -pdevpart
/usr/field/dskx [ options ] -cdev
Description
The exerciser tests the disk drives on your system. The exerciser has three main options which include read only, write/read/validate data
on a partition, and write/read/validate data of a disk.
The exerciser does random seeks and reads of random block sizes and random seeks, writes, reads, and validations of random data patterns of
random block sizes. The exerciser will run until or kill -15 pid is sent to the process.
A logfile is made in for you to examine and then remove. If there are errors in the logfile, make sure you check the file, because that is
where the driver and kernel error messages are saved.
CAUTION: Both the -c and -p options of the exerciser destroy data on the disk. Use extreme caution before using them on any non-scratch
media. If you are unsure of what data is on the disk, contact your system manager before running with either of these options.
Arguments
One of the following function flags and arguments must be specified.
-rdev Performs a random read-only test on all partitions except the c partition. The dev argument can be a raw or buffered device name
and number. For example, rhp0, ra3, hk1.
-pdevpart Writes, reads, and validates data from the device name and number specified by dev and the partition specified by part. The dev
argument can be a raw or buffered device name and number. For example, rhp0, ra3, hk1. The part argument can be any valid par-
tition from a - h.
CAUTION: Be careful when exercising partitions that overlap other partitions, as you may inadvertently destroy data on a parti-
tion that you do not want to test. You can use the -q option of the command to see what partitions overlap on the device on your
system.
-cdev Writes, reads, and validates data from all partitions except the c partition on the device specified by dev. The dev argument
can be a raw or buffered device name and number. For example, rhp0, ra3, hk1.
Options
The options are:
-h Prints help message for the command.
-ofile Saves output diagnostics in file.
-tn Specifies the run time in minutes (n). The default is to run until the process receives a or kill -15 pid.
-dm Prints statistics every m minutes.
Restrictions
If there is a need to run a system exerciser over an NFS link or on a diskless system there are some restrictions. For exercisers that
need to write into a file system, such as the target file system must be writable by root. Also the directory, in which any of the exer-
cisers are executed, must be writable by root because temporary files are written into the current directory. These latter restrictions
are sometimes difficult to overcome because often NFS file systems are mounted in a way that prevents root from writing into them. Some of
the restrictions may be overcome by copying the exerciser to another directory and then executing it.
Examples
The following example exercises RA disk unit 1, for 60 minutes in the background:
% /usr/field/dskx -t60 -cra1 &
The following example exercises raw HP disk unit 0, partition d, until or kill -15 pid:
% /usr/field/dskx -prhp0d
See Also
Guide to System Exercisers
dskx(8)