This should mirror the performance of a typical RAID10 SAN with hard drives Limiting the disk to 600 IOPS and introducing 7ms of latency. 1144 IOPS / 5025 physical reads per second / 99.85% util.While the default fio settings are not representative of the WiredTiger workload, we have found this configuration to be a good approximation of WiredTiger disk utilization.Īll tests were repeated under three disk scenarios: Scenario 1ĭefault disk settings provided by a AWS c5 io1 100GB volume. We performed tests on 10GB of data, the ioengine of psync, and with reads ranging between 4kb and 32kb. We generally test with fio, the Flexible IO Tester. If the observed disk performance is in question, performing an IO test can be very helpful. While cloud providers may provide an IOPS threshold for a given volume and disk, and disk manufacturers publish expected performance numbers, the actual results on your system may vary. While this number can be confusing, it is a good indicator of overall disk health. Utilization indicates what percentage of these queues is busy at a given time. Linux has multiple queues per device for servicing IO. A high end PCIe attached NVMe device could offer 1,500,000 IOPS while a typical hard disk may only support 150 IOPS. Should you reach this threshold, any further accesses will be queued, resulting in a disk bottleneck. A given cloud provider may guarantee a certain number of IOPS for a given drive. Disk IOPS (Input/Output Operations Per Second).High latencies indicate disks have trouble keeping up with the given workload. For SSDs, latencies are typically under 3ms. On Linux this is represented by await, the time in milliseconds from an application issuing a read or write before the data is written or returned to the application. Note that many cloud providers limit the disk throughput or bandwidth. Random read and write performance in the 4kb range is the most representative of standard database workloads. This is usually measured in megabytes per second.
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