Size Recommendation

Size Recommendation

The Size Recommendation This article will give you some technical tips on how to use your Synology NAS as iSCSI storage for the VMware environment, and will cover the following topics:

• Size of recommendations
• Multi-lane I / O connectivity
• Manage performance

The first two questions raised when choosing NAS Synology as VMware storage might be "How do I choose the Synology NAS model? In using the VMware environment, it is important to know whether the storage system can meet the workload requirements. 

The number of IOPS (Operation Input / Output Per Second) usually functions as a measure of the starting point for this purpose. In this section, we will provide resources for estimating IOPS from the production environment as well as information about random IOPS from the Synology NAS server.

Estimating Size Recommended Workloads

To estimate the workload of your production environment, you can visit the Synology Blog Officer for useful techniques on How to measure IOPS for VMware and How to measure IOPS for Windows. There are also third-party tools, such as VeeamONE or others (available by searching for "VMware server monitoring"), which provides an easy-to-use GUI for IT administrators to obtain performance data and capacity information and their virtualized environmental health.

Measuring Storage Performance Recommended Size

The workload of virtualized environments mostly involves random IOPS. The number of random IOPS is usually a storage performance indicator, which can help decide on a storage system that best meets the demands of the workload. 

Information about the maximum random IOPS of the Synology NAS model is available on the Synology Product Performance Page, here partially duplicated below for quick reference. The picture above illustrates the maximum IOPS of random read / write from Synology XS / XS. The series model is fully loaded with SSD in a 10GbE environment in Size Recommendation. 

Actual performance may be slower with an installed hard disk drive, with around 75 reading random per disk SATA IOPS and 150 read random IOPS per SAS drive. Writing performance will be 75% slower than reading performance if RAID 5 is used. 

Overall performance can be calculated by multiplying IOPS per disk with the number of disks installed. Activating the SSD cache is highly recommended, because it usually gives a cache of three or more performance improvements, depending on the type of workload. 

For example, 10 SATA drives together with two SSDs for cache will give around 2,250 IOPS random readings (75 * 10 * 3 = 2250). For more information about SSD cache, please read Using Synology SSD Technology to Improve System Performance. 

Please note that the numbers above are only rough estimates. The rule of thumb recommends ordering 20% ​​or more as a buffer for allowing further adjustments based on environmental performance. The generally accepted industry standard for latency datastore is 20 ms or less. In the case of high latency on individual VMware data, consider expanding the SSD cache size or using a special volume consisting entirely of SSDs for this iSCSI LUN to store the VM.