David Beroff
Well-known member
- Joined
- Jun 14, 2016
- Messages
- 1,510
- Points
- 63
As much as I have read about iowait, it is still confusing to me. What percentage of iowait is considered is good or high?
What percentage is considered as a good IOWait?
- Thread starter David Beroff
- Start date
VirtuBox
Well-known member
- Joined
- May 3, 2016
- Messages
- 1,622
- Points
- 83
IOWait is time that the processor/processors (cores) are waiting to process/compute a task. If CPU cores are waiting, it's because there is already several disk I/O requests and the disk is not able to handle more requests. So if you have a high IOWait percentage, that mean your CPU can handle more computational work but your not your disk.
If it is constantly high, your disks are a bottleneck and they slow your system down, but it depend on your CPU cores and performance against your disk IOPS.
For example, to process the same program, IOWait percentage will be higher if you have 12 Cores than if you have 6 cores, and it will be lower if your have SSD disks, than if you have classic hard drives.
Denis // trabia
Member
- Joined
- May 29, 2017
- Messages
- 50
- Points
- 6
You can use vmstat command to see the disk performance and not only.
For example running
will run the test 20 times with a 1 second interval and give you the output.
What you are interested here is the last column (wa) which is the amount of time that the processor spends waiting for IO operations to complete before being able to continue processing tasks. Ideally it should be 0.
More you can read here: https://www.thomas-krenn.com/en/wiki/Linux_Performance_Measurements_using_vmstat
For example running
Code:
vmstat 1 20
Code:
$ vmstat 1 20
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
0 0 3996 168488 57100 1368636 0 0 1 2 0 0 3 1 97 0
0 0 3996 168604 57100 1368728 0 0 0 0 144 303 1 0 100 0
0 0 3996 168604 57100 1368984 0 0 256 0 162 464 1 0 99 0
0 0 3996 168604 57100 1368972 0 0 0 0 239 638 3 0 97 0
0 0 3996 168604 57100 1368952 0 0 0 0 242 529 1 1 99 0
0 0 3996 168604 57100 1368952 0 0 0 0 148 430 1 0 99 0
1 0 3996 168604 57100 1368952 0 0 0 0 222 451 6 0 94 0
0 0 3996 168604 57100 1368952 0 0 0 0 141 270 2 0 98 0
0 0 3996 168604 57100 1368952 0 0 0 0 166 450 1 0 99 0
0 0 3996 168604 57100 1368952 0 0 0 0 133 410 0 0 99 0
0 0 3996 168604 57100 1368952 0 0 0 0 196 398 0 0 99 0
0 0 3996 168604 57100 1368952 0 0 0 0 187 510 1 0 100 0
0 0 3996 168604 57108 1368952 0 0 0 16 263 677 2 0 97 1
0 0 3996 168604 57108 1368952 0 0 0 0 205 431 1 0 98 0
0 0 3996 168604 57108 1368964 0 0 0 0 179 467 1 0 98 0
0 0 3996 168604 57108 1368964 0 0 0 0 169 446 2 0 98 0
0 0 3996 168604 57108 1368964 0 0 0 0 202 365 2 0 98 0
0 0 3996 168604 57108 1369208 0 0 256 0 226 458 2 1 96 0
0 0 3996 168604 57108 1369208 0 0 0 40 202 501 2 0 98 0
0 0 3996 168604 57108 1369220 0 0 0 0 154 295 2 0 98 0More you can read here: https://www.thomas-krenn.com/en/wiki/Linux_Performance_Measurements_using_vmstat
Older Threads
Newer Threads
Latest Threads
Recommended Threads
Similar Threads
Latest postsNew threads
-
New threads
-
-
Hello Everyone – I'm Glad to Join
- Started by Marvin Accuweb.Cloud
- Replies: 4
-
ENGINYRING - Your Alternative to Corporate Hosting Giants
- Started by hetnix_srl
- Replies: 3
-
Latest Hosting OffersNew Reviews
-
Latest hosting offers
-
Hostaddon VPS/VDS | EU/US/ASIA | 25/10/2/1 Gbps | SSD NVMe | Upto 50% Off | Storage | DMCA IgnoreUnmetered 1, 10, 25 Gbps Unmetered VPS Hosting- HostAddon
- Updated:
-
30 Days Free VPS Windows or Linux with Monthly Contract backed by NVMe SSD SANVPS customisble resources- trulycloud
- Updated:
-
iWebFusion | USA SIX LOCATIONS | E3|E5|EPYC|RYZEN | Support Aliay&USDTUSA dedicated server- Vanessa
- Updated:
-
