Crystal Disk Mark Random
Teodolinda Mattson
You can get IOPs, latency, and throughput numbers from CrystalDiskMark too by clicking File, Save Text, then go into a text editor and open the results. The text version of the results has more details:
Brent, thanks for the helpful articles I really appreciate them. I just ran this on the data drive of a new win2k8r2, SQL 2008 r2 OLTP test cluster. Here are the numbers. I think they look OK but not 100%sure. Thoughts?
I use CrystalDiskMark quite a bit. In my experience, the main numbers you want to look at / optimize for are sequential reads for table/index scans, and something in between the 512K and 4K random reads for the rest of an OLTP workload.
Hello Brent, I am having trouble reading the results from Crystal Disk Mark. I am using a NetApp for the sql server data files and a raid 10 for the OS. I am running SQL Server 2008 R2 Enterprise x64 on Server 2008 R2 Enterprise (this is a cluster). I went through the bandwidth reference poster and I still dont understand the results.
Quick question, my new server (software raid) shows 284 mb/S and my old server shows 3000 mb/S
(Hardware raid controller). Does the hardware controller really boost the performance that much?
Steve
9 Runs of 4Gb in Crystal Mark, each San Controller has 16Gb cache so that may be affecting results.
The Test Server is HyperV 2012R2 (running on a 3 Node HyperV 2012 R2 cluster). The test drive is a Dynamic .vhdx of 100Gb dedicated for the test. No other SAN activity is occuring at the time of these tests as it is PreProd.
We had a client who had the same setup, I would be worried if there is any sharing of the SAN with Exchange. We finally convinced them to separate them and wow all is good. Too many background functions in Exchange that happen that killed the server.
Hi guys, I am a rather novice in SQL matters but have been Reading quite a lot of your articles and find it very interesting and helpful. We have a customer where we have installed an application using SQL as DB Engine, and since the customer moved the entire installation to a Blade server with storage on a SAN we have experienced problems with slowness in our application (which is constantly using SQL). Customer has all SQL databases and Log file placed on the E: drive, which is the same logical drive as C (which i suspect is on SAN storage, and most likely shared with numeruous other applications. I Was running CrystalDiskMark on the E: drive (and got this result:
I do not like much this test tool CrystalDiskMark 6.0.2 x64 because it is next to impossible to analyze the results logically, systematically!
There should be for each row of the results screen output, for each particular device tested (SSD, HD, etc.), a bracket of acceptable values. Outside this bracket of acceptable values, you would have values that indicate problems with your hardware device. Nothing of the sort exist.
For those working in a DOE shop, there is something called WLS from the Kansas City Plant you may be obliged to run for security purposes. WLS does interfere with the CrystalDiskMark benchmark by keeping a handle open on the temp file that CrystalDiskMark creates. For larger files this causes CrystalDiskMark to report zero (0) MB/s Write speeds.
This tool is Useless I cannot get any speed check on one of my perfectely functioning HDD, I get an error message. And no body knows what it means. This is not an acceptable answer for this company software.
I have a laptop HDD which is around 8 years old. I feel that the hard disk is very slow, in many cases, I notice the "Active Time" in Windows Task Manager is 100% after logging in and when doing operations like opening an application. I did a benchmark, and here is the result.
That is perfectly normal for random I/O performance on a 5400 rpm disk. A 5400 rpm disk can manage about 90 IOPS because the required sector will only go under the head 90 times per second (5400 times per minute).
Average random rotational latency is directly dependent on drive rotation speed. Disks come in a variety of speeds, from 5400 RPM (revolutions per minute), which is quite standard for the smaller consumer 2.5" disks, up to 15000 RPM for high-end enterprise-grade disks.
The Q32T1 test leverages queuing: multiple read commands (up to 32) are sent to the drive before waiting for the results (and as soon as a result comes back, a new read is requested, maintaining a queue of 32 pending reads).
This enables the drive to reorder the reads so they're less random. For instance, the seek time is shorter when going from track 1 to track 2 than from the first to the last, so ordering the reads on increasing tracks saves time. It also helps if several blocks are read from the same track (no seeking, and you can read the first block coming under the read/write head).
Awhile back, I made a video about USBc and the classic Mac Pro but lamented yet ago the terrible benchmarking on macOS. The first commenter on FaceBook pointed out that we finally have a good disk benchmark utility AmorphousDiskMark. While it isn't a direct port, it's heavily inspired by the famed and loved Windows utility, CrystalDiskMark.
BlackMagic's Disk Speed Test only tests one thing, continuous throughput. This is useful but only measures one aspect of an SSD, and doesn't necessarily mimic accurately how most disk interactions occur. Random Read and Write tests are as important, if not more so, as many SSDs can deliver fast maximum continuous read and writes but much less so for random small data blocks. CrystalDiskMark tests random reads and writes both as queued requests and single requests. The default depth is pretty high for the test. Usually, an OS wouldn't have that deep of a queue, but the Q1T1 does mimic a singular request. Also, CrystalDiskMark measures IOPS (Input/Output Operations-per-second), which is similar but also a different measure of disk speed.
There's plenty of aspects that aren't covered, such as latency, burst performance, power consumed, and mixed random read/writes, but this is a massive step in the right direction for gauging SSD performance on macOS. Oh yeah, and it's free.
CrystalDiskMark has been around for over a decade and it's one of the PC community's favorite ways to benchmark storage, whether it's hard drives, solid-state drives (SSD), or even flash drives. It's a simple, one-click benchmark that tells you how fast your storage is. But what exactly is it testing, and what do the results mean for your hardware? Here's what you need to know.
CrystalDiskMark is a Windows storage benchmark that first came out in 2008 that attempts to judge how fast a drive is under set testing conditions. There's also a macOS benchmark called AmorphousDiskMark, which is supposed to work more or less in the same way and is designed (with the permission of the author of CrystalDiskMark) to look the same way. At its very core, all CrystalDiskMark is doing is transferring files and telling you the speed at which the drive was able to transfer that data.
Before running your tests, you'll need to set a working file size. This is the file size that CrystalDiskMark creates to perform read and write tests on, and it ranges from 16MB to 64GB. Leaving it at the default of 1GB is completely fine, as it's a realistic size for a lot of data that you may access on your storage.
CrystalDiskMark comes with four preset benchmarks, but if you look in the advanced settings, you can actually customize what the benchmark tests for and get different results. CrystalDiskMark benchmarks come down to the four important testing parameters: sequential vs. random, block size, queue depth, and threads.
The two basic types of tests CrystalDiskMark uses are sequential and random, denoted by SEQ and RND respectively. The main difference between these two kinds of workloads is how the data is organized. In a sequential workload, the data the SSD is accessing is physically contiguous and can be accessed one after the other in a sequence (hence sequential). Random workloads involve data that isn't sequential or contiguous and may be spread all over the drive. Depending on other factors, the performance difference between sequential and random can range from minor to extremely large.
Generally speaking, SSDs are very good at handling random workloads while HDDs struggle with them, which is why you may see HDDs get rated speeds of less than 10MB/s in CrystalDiskMark's random tests but over 100MB/s in sequential ones. This is down to the fact that HDDs have to mechanically move a component that reads and writes from the physical disk, and it takes quite a bit of time jumping from place to place. Although SSDs aren't mechanical, they still process random workloads slower than sequential ones for external reasons.
Files are made up of blocks and are the largest pieces of data that are moved in one input/output (or I/O) operation. In the default tests that CrystalDiskMark presents you with, you'll see some that use a 1MiB block size (roughly one megabyte), some that use a 4KiB block size (roughly four kilobytes), and one that uses a 128KiB block size (roughly 128 kilobytes).
This might seem counterintuitive, but the larger the block size, the faster the transfer speed. It's basically the difference between moving one piece of paper at a time and moving a whole folder into a filing cabinet. Sequential file transfers often involve large blocks, while random workloads tend to use smaller blocks. Although CrystalDiskMark uses large block sizes in sequential tests and small block sizes in random tests, block size isn't necessarily indicative of sequentialness or randomness.
Queue depth refers to how many queues are handling I/O requests at any given time, and with more queues open to transfer data, there's a greater potential for faster transfer speeds. By default, CrystalDiskMark tests at queue depths of 1, 8, and 32, though you can manually increase the queue depth and test that way if you wish. You can imagine a queue as an individual worker filing documents away, and obviously, more workers mean faster filing.
d3342ee215