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Operating Systems SCO How to measure disk IO 5.0.7? (sar, return values ​​are not valid) Post 302907459 by flako on Saturday 28th of June 2014 09:16:10 AM
Old 06-28-2014
How to measure disk IO 5.0.7? (sar, return values ​​are not valid)

Hello
I am analyzing disk performance OSR5.0.7 running inside VirtualBox.
GUEST: osr5.0.7; 1GB ram; raw disk
HOST: SLES11SP3, 4GB ram; 1 disc SATA2-7200rpm

But I'm not sure how to do it right (the values ​​returned by sar not match the values ​​of the physical machine)

The attributes analyzed are:
blks/s: if not int or out, but converted to MB/s should be: blks/s * 512 /1024 /1024
bread/s: I understand you are the KB/s read from the disk that are not in the cache, with this iconclude that it is the ratio of the hard disk read.
bwrit/s: I understand you are the KB/s written when a flush is done, so i conclude that it is the ratio of the hard disk write.


To measure the performance I use the command:
time sh -c "dd if=/dev/zero of=pruebaHD-4254.dd count=131072 bs=8k ibs=8k conv=sync && sync"
Generating a file the size of the ram and then calculate the MB/s based on the value returned by time (repeat the process with different sizes of bs, then iterate 3 times)


With that understanding, when I see I have the values:
blks/s : max: 86.98 MB/s avg: 16.77 MB/s
bread/s : max: 3.10 MB/s avg: 241.66 KB/s
bwrit/s : max: 86.98 MB/s avg: 16.12 MB/s


According to "time dd" achievement Min: 20MB/s Max: 43MB/s Avg: 30MB/s.
According zabbix host 36MB/s

Since the values ​​are not similar, they conclude that something is wrong in my analysis.
I am misunderstanding sar values​​?
It is a misconception and I'm looking at it all wrong?
How I can know the ratio I / O disk presicion in OSR5.0.7?

thanks
 

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sar(1)								   User Commands							    sar(1)

NAME
sar - system activity reporter SYNOPSIS
sar [-aAbcdgkmpqruvwy] [-o filename] t [n] sar [-aAbcdgkmpqruvwy] [-e time] [-f filename] [-i sec] [-s time] DESCRIPTION
In the first instance, the sar utility samples cumulative activity counters in the operating system at n intervals of t seconds, where t should be 5 or greater. If t is specified with more than one option, all headers are printed together and the output can be difficult to read. (If the sampling interval is less than 5, the activity of sar itself can affect the sample.) If the -o option is specified, it saves the samples in filename in binary format. The default value of n is 1. In the second instance, no sampling interval is specified. sar extracts data from a previously recorded filename, either the one specified by the -f option or, by default, the standard system activity daily data file /var/adm/sa/sadd for the current day dd. The starting and ending times of the report can be bounded using the -e and -s arguments with time specified in the form hh[:mm[:ss]]. The -i option selects records at sec second intervals. Otherwise, all intervals found in the data file are reported. OPTIONS
The following options modify the subsets of information reported by sar. -a Reports use of file access system routines: iget/s, namei/s, dirblk/s -A Reports all data. Equivalent to -abcdgkmpqruvwy. -b Reports buffer activity: bread/s, bwrit/s transfers per second of data between system buffers and disk or other block devices. lread/s, lwrit/s accesses of system buffers. %rcache, %wcache cache hit ratios, that is, (1-bread/lread) as a percentage. pread/s, pwrit/s transfers using raw (physical) device mechanism. If run in a non-global zone and the pools facility is active, these values reflect activity on the processors of the pro- cessor set of the pool to which the zone is bound. -c Reports system calls: scall/s system calls of all types. sread/s, swrit/s, fork/s, exec/s specific system calls. rchar/s, wchar/s characters transferred by read and write system calls. No incoming or outgoing exec(2) and fork(2) calls are reported. If run in a non-global zone and the pools facility is active, these values reflect activity on the processors of the pro- cessor set of the pool to which the zone is bound. -d Reports activity for each block device (for example, disk or tape drive) with the exception of XDC disks and tape drives. When data is displayed, the device specification dsk- is generally used to represent a disk drive. The device specification used to represent a tape drive is machine dependent. The activity data reported is: %busy, avque portion of time device was busy servicing a transfer request, average number of requests outstanding during that time. read/s, write/s, blks/s number of read/write transfers from or to device, number of bytes transferred in 512-byte units. avwait average wait time in milliseconds. avserv average service time in milliseconds. For more general system statistics, use iostat(1M), sar(1M), or vmstat(1M). See System Administration Guide: Basic Administration for naming conventions for disks. -e time Selects data up to time. Default is 18:00. -f filename Uses filename as the data source for sar. Default is the current daily data file /var/adm/sa/sadd. -g Reports paging activities: pgout/s page-out requests per second. ppgout/s pages paged-out per second. pgfree/s pages per second placed on the free list by the page stealing daemon. pgscan/s pages per second scanned by the page stealing daemon. %ufs_ipf the percentage of UFS inodes taken off the freelist by iget which had reusable pages associated with them. These pages are flushed and cannot be reclaimed by processes. Thus, this is the percentage of igets with page flushes. If run in a non-global zone and the pools facility is active, these values reflect activity on the processors of the pro- cessor set of the pool to which the zone is bound. -i sec Selects data at intervals as close as possible to sec seconds. -k Reports kernel memory allocation (KMA) activities: sml_mem, alloc, fail information about the memory pool reserving and allocating space for small requests: the amount of memory in bytes KMA has for the small pool, the number of bytes allocated to satisfy requests for small amounts of memory, and the number of requests for small amounts of memory that were not satisfied (failed). lg_mem, alloc, fail information for the large memory pool (analogous to the information for the small memory pool). ovsz_alloc, fail the amount of memory allocated for oversize requests and the number of oversize requests which could not be satisfied (because oversized memory is allocated dynamically, there is not a pool). -m Reports message and semaphore activities: msg/s, sema/s primitives per second. If run in a non-global zone and the pools facility is active, these values reflect activity on the processors of the pro- cessor set of the pool to which the zone is bound. -o filename Saves samples in file, filename, in binary format. -p Reports paging activities: atch/s page faults per second that are satisfied by reclaiming a page currently in memory (attaches per second). pgin/s page-in requests per second. ppgin/s pages paged-in per second. pflt/s page faults from protection errors per second (illegal access to page) or "copy-on-writes". vflt/s address translation page faults per second (valid page not in memory). slock/s faults per second caused by software lock requests requiring physical I/O. If run in a non-global zone and the pools facility is active, these values reflect activity on the processors of the pro- cessor set of the pool to which the zone is bound. -q Reports average queue length while occupied, and percent of time occupied: runq-sz, %runocc Run queue of kernel threads in memory and runnable swpq-sz, %swpocc Swap queue of processes -r Reports unused memory pages and disk blocks: freemem average pages available to user processes. freeswap disk blocks available for page swapping. -s time Selects data later than time in the form hh[:mm]. Default is 08:00. -u Reports CPU utilization (the default): %usr, %sys, %wio, %idle portion of time running in user mode, running in system mode, idle with some process waiting for block I/O, and other- wise idle. If run in a non-global zone and the pools facility is active, these values reflect activity on the processors of the pro- cessor set of the pool to which the zone is bound. -v Reports status of process, i-node, file tables: proc-sz, inod-sz, file-sz, lock-sz entries/size for each table, evaluated once at sampling point. ov overflows that occur between sampling points for each table. -w Reports system swapping and switching activity: swpin/s, swpot/s, bswin/s, bswot/s number of transfers and number of 512-byte units transferred for swapins and swapouts (including initial loading of some programs). pswch/s process switches. If run in a non-global zone and the pools facility is active, these values reflect activity on the processors of the pro- cessor set of the pool to which the zone is bound. -y Reports TTY device activity: rawch/s, canch/s, outch/s input character rate, input character rate processed by canon, output character rate. rcvin/s, xmtin/s, mdmin/s receive, transmit and modem interrupt rates. If run in a non-global zone and the pools facility is active, these values reflect activity on the processors of the pro- cessor set of the pool to which the zone is bound. EXAMPLES
Example 1: Viewing System Activity The following example displays today's CPU activity so far: example% sar Example 2: Watching System Activity Evolve To watch CPU activity evolve for 10 minutes and save data: example% sar -o temp 60 10 Example 3: Reviewing Disk and Tape Activity To later review disk and tape activity from that period: example% sar -d -f temp FILES
/var/adm/sa/sadd daily data file, where dd are digits representing the day of the month ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWaccu | +-----------------------------+-----------------------------+ SEE ALSO
sag(1), iostat(1M), sar(1M), vmstat(1M), exec(2), fork(2), attributes(5) System Administration Guide: Basic Administration NOTES
The sum of CPU utilization might vary slightly from 100 because of rounding errors in the production of a percentage figure. SunOS 5.10 24 Jul 2004 sar(1)
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