→ Applies to: SynetoOS 5.x
Step 1. Connect to SynetoOS appliance via SSH as admin
ssh admin@<your_ip_address_or_hostname>
Step 2. Become Super User
sudo su
Step 3. Run to check I/O usage of disks
iostat -xz 1| Parameter | Usage |
| -x | Displays eXtended statistics |
| -z | Suppresses output for devices with zero activity |
| -k | Displays statistics in Kilobytes (KB) |
| -m | Displays statistics in Megabytes (MB). Recommended for high-performance storage systems |
| -t | Displays a timestamp for each report |
| -c | Displays CPU statistics only |
| -d | Displays Device reports only |
| -p ALL | Displays statistics for all devices and their individual partitions |
| -j ID | Displays persistent device names using their ID instead of device name |
| -N | Displays statistics for LVM logical volumes |
| 1 | Updates every second |
EXAMPLE OUTPUT
Linux 5.4.0-66-generic (hostname) 05/20/2024 _x86_64_ (4 CPU) avg-cpu: %user %nice %system %iowait %steal %idle 0.15 0.00 0.10 0.00 0.00 99.75 Device r/s w/s rkB/s wkB/s rrqm/s wrqm/s r_await w_await aqu-sz rareq-sz wareq-sz svctm %util sda 0.00 0.10 0.00 0.85 0.00 0.00 0.00 0.00 0.00 0.00 8.50 0.00 0.00
| Column Descriptions - CPU Section (CPU Usage Metrics) | |
| avg-cpu | Description |
| %user | Percentage of CPU time spent in user mode. |
| %nice | Percentage of CPU time spent by processes with modified priority (niceness value). |
| %system | Percentage of CPU time spent in kernel mode (or system mode). |
| %iowait | Percentage of CPU time spent waiting for I/O (Input/Output) to complete. |
| %steal | Percentage of CPU time stolen by virtual machines (hypervisor wait time). |
| %idle | Percentage of CPU time that was idle (not used by anything). |
| Column Descriptions - Device Section (Storage I/O Metrics) | |
| Device | Description |
| Device | Name of the device. |
| r/s | Reads completed per second. |
| w/s | Writes completed per second. |
| rkB/s | Kilobytes read per second. |
| wkB/s | Kilobytes written per second. |
| rrqm/s | Read requests merged per second. |
| wrqm/s | Write requests merged per second. |
| r_await | Average wait time for completed reads, in milliseconds (ms). |
| w_await | Average wait time for completed writes, in milliseconds (ms). |
| aqu-sz | Average size of the I/O request wait queue. |
| rareq-sz | Average size of read requests (in KB if “-k” is specified). |
| wareq-sz | Average size of write requests (in KB if “-k” is specified). |
| svctm | Average service time for I/O requests, in milliseconds (ms). |
| %util | Percentage of device utilization. Indicates how busy the device was during the sampling interval. A value near 100% indicates that the device is fully utilized. |