How to measure IOPS with linux
So many times I need to measure the amount of IOPS on a Linux disk/storage system. While there are many tools for the jobs they just don’t seem to give you a ‘number’. For example Splunk indexers require 1200+ IOPS according to hardware recommendation guides but how do you find out if your any where close to that number? Use ‘bonnie++’, ‘iozone’ or perhaps ‘fio’? Well use any of those tools will create the type of read / write sequence you would like to replicate - but where the damn magic number???
Easiest two ways are:
Method #1:
run iozone -a (or bonnie++) in one screen then in another session / terminal use nmon, pressing D (capital D) to get disk stats and get the number from the Xfers column. This is your magic number (or IOPS reading)
┌nmon─14i─────────────────────Hostname=reddragon─────Refresh= 2secs ───19:51.57─ │ Disk I/O ──/proc/diskstats────mostly in KB/s─────Warning:contains duplicates─ │DiskName Busy Read Write Xfers Size Peak% Peak-RW InFlight │sda 99% 699.9 14.0KB/s 178.0 4.0KB 493% 3658.8KB/s 1 │sda1 0% 0.0 0.0KB/s 0.0 0.0KB 0% 0.0KB/s 0 │sda2 99% 699.9 14.0KB/s 178.0 4.0KB 493% 3658.8KB/s 1 │dm-0 0% 0.0 0.0KB/s 0.0 0.0KB 0% 0.0KB/s 0 │dm-1 99% 699.9 14.0KB/s 178.5 4.0KB 494% 3658.8KB/s 1 │dm-2 0% 0.0 0.0KB/s 0.0 0.0KB 76% 2553.5KB/s 0 │Totals Read-MB/s=2.1 Writes-MB/s=0.0 Transfers/sec=534.4
In the above example I’m getting about 178 IOPS for my disk ’sda’
Method #2:
run fio with the correct workload (google how to use fio) and while it’s running it will actually tell you the IOPS.
[root@reddragon ~]# fio random-read-test.fio random-read: (g=0): rw=randread, bs=4K-4K/4K-4K/4K-4K, ioengine=sync, iodepth=1 fio-2.0.13 Starting 1 process Jobs: 1 (f=1): [r] [85.1% done] [736K/0K/0K /s] [184 /0 /0 iops] [eta 00m:28s]
In this example I am getting 184 IOPS. Also if you wait until fio finishes it run - you can the IOPS reading from there. Eg.
random-read: (g=0): rw=randread, bs=4K-4K/4K-4K/4K-4K, ioengine=sync, iodepth=1 fio-2.0.13 Starting 1 process Jobs: 1 (f=1): [r] [98.9% done] [2224K/0K/0K /s] [556 /0 /0 iops] [eta 00m:02s] random-read: (groupid=0, jobs=1): err= 0: pid=7239: Tue Feb 25 16:49:16 2014 read : io=131072KB, bw=747406 B/s, iops=182 , runt=179578msec clat (usec): min=107 , max=117530 , avg=5473.62, stdev=4112.08 lat (usec): min=107 , max=117531 , avg=5473.93, stdev=4112.08 clat percentiles (usec): | 1.00th=[ 245], 5.00th=[ 302], 10.00th=[ 370], 20.00th=[ 2480], <SNIP>
As you can see: iops=182 - pretty consistent with the other results!
Squid ICAP Syntax with F-Secure Internet Gate Keeper (IGK)
*** UPDATE September 2015 - This article has been updated with the correct syntax and confirmed working on Squid 3.3.8 ***
The doco for IGK is some what lacking for the ICAP settings but it does mention ” Refer to the documentation of the proxy for information on how to set it up”. That’s not very helpful so I contacted F-Secure technical support and asked them. This is the reply:
You will need to add these lines to Squid config file:
icap_enable on icap_send_client_ip on icap_service service_req reqmod_precache bypass=1 icap://[IP address of IGK]:1344/request adaptation_access service_req allow all icap_service service_resp respmod_precache bypass=0 icap://[IP address of IGK]:1344/response adaptation_access service_resp allow all
Unfortunately that still doesn’t work for some unknown reason and I am only getting the error:
ErrPage: ERR_CANNOT_FORWARD
I don’t have anymore time to spend on this, I guess I’ll just use the F-Secure HTTP proxy as a parent proxy for squid.