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Qvr client crashes2/24/2023 QNAP NAS storage supports different types of RAID Level, each RAID Level have different capacity and performance metrics. QNAP SSD Read/Write caching feature helps random IOPS performance by re-sorting (reducing write) block addresses in cache to reduce load on back-end disks.Ĭache size impact, larger the better (to create more opportunities for re-sorting), but practically limited by cost because write caches are far more expensive than back-end disk. Since flash drives do not have a physical disk head that must move around, there is no 10 ms seek time penalty that comes from a mechanical disk. Why Flash (SSD) Read/Write caching improves random IOPS But if you do 100 random writes of 1MB each, that will take a total of 4 seconds (3 seconds for the actual writing, and 10 ms * 100 = 1 second for all the seeking). So if you sequentially write 100 MB of data to a disk, it will take around 3 seconds. Sequentially writing data to that same disk takes about 30 ms per MB. During random I/O, the position of the disk head, seek disk rotational delay, and seek time will cause significant performance penalty.įor mechanical disk-based systems, where each disk seek will take around 10ms. Random access involves a higher number of seek operations, which means random read and especially random write will deliver a lower rate of throughput and IOPS. Sequential I/O on mechanical drives can generally be served at a higher throughput because there is less seek operation by the disk head and at the same time larger data segment can be read/written during a single platter rotation. The seek operation, which occurs when the disk head positions itself at the right disk cylinder to access the requested data, takes more time than any other part of the I/O process.ĭue to the nature of mechanical drives, accessing/writing data sequentially is much faster than accessing/writing it randomly because of the way in which the disk hardware works. Video streaming (Watching a video from the NAS).Video editing (Direct editing by using video editing software from a single work station).Work load pattern that are mostly sequential access. Sequential means you must first read the first part of the file, before reading second, then third etc. Work load pattern that are mostly random access. So for example, you can read the middle part before the start. Random access means you can get any part of the file in any order. We can calculate this by taking the total number of drives multiply by the number of RAW IOPS for each drive (4 HDD x 125 IOP = 500 IOPS). To do a basic RAW IOPS calculation for 4 hard drives at 7,200 RPM, we can assume the total RAW IOPS are 500 IOPS. * Performance depends on SSD controller chip and flash cell General hard drive IOPS characteristics Device Each disk in you storage system can provide a certain amount of IOPS based off of the rotational speed, average latency and average seek time. One read request or one write request = 1 IOPS. The most common performance characteristics measured are sequential and random operations. We measure disk performance in IOPS or Input/Output per second. Match the appropriate drive type to the expected workload within your environment. * An example on how SSD cache pool is accessed within QNAP NAS.Įssential guide lines on choosing the right type of media for your QNAP NAS storage. “Thin Volume” option provides better flexibility, but may decrease storage performance for sensitive application. Use “Static Volume” for best performance or use “Thick Volume” under storage pool.Create a RAID 10 Storage Pool. See Appendix for explanation.Choose the right configuration for RAID and Volume.Use mSATA and SSD drives for Read/Write caching available on QTS 4.2.0, using 2 or 4 SSD and create RAID 1 or 10 as the caching pool.Higher end enterprise platform is equipped with faster CPU, Memory, and IO specification. Choose a appropriate enterprise QNAP NAS storage.The guide line below introduces specific configuration recommendations that enable good performance from a QNAP storage system. How to achieve the best possible storage performance: In this best practice we will provide recommendations on how to configure the QNAP storage for optimal performance depending on your work load. This best practice is intended for QNAP users, partners, and customers who are considering using QNAP NAS systems. This best practice guide provides general recommendation for configuring QNAP NAS storage systems for best performance.
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