Tencent Cloud Account: Standard Cloud Disk Performance Depth Measurement
For many individual developers or small and medium-sized enterprises who have just come into contact with cloud computing, when buying Tengxun Cloud Server (CVM) for optional storage, they are often confused by a lot of professional terms:
High-performance cloud disk, standard SSD, universal SSD, speed SSD......
Among them, "standard cloud disk" (also called high-performance cloud disk in some old documents) is often used as the first choice for entry because of its price. But as the saying goes, "you get what you pay for", many friends are murmuring in their hearts: Is this stuff reliable? Will it get stuck if you hang a website? Can you run a small database?
In order to help everyone avoid the pit, we opened a Tencent cloud instance at our own expense and conducted a 24-hour "extreme pressure test" specifically for standard cloud disks (CBS) ". Today's article, without talking about the empty official PPT, uses the most real test data and real perspective to show you all the ins and outs of it.
Introduction to 1. Test Players and Test Environment
In order to ensure the objectivity of the test results, we avoid the performance bottleneck of other hardware. The test environment we chose this time is as follows:
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Test Model: Tengxun Cloud Standard S5 Instance (4-Core 8G)
Operating System: Ubuntu 22.04 LTS
Test disk object: tengxun cloud standard cloud disk (capacity: 100 GiB, mounted as a data disk)
Testing tool: FIO(Flexible I/O Tester), the most authoritative disk performance testing tool in Linux field
⚠Knock on Blackboard: "Calculation Force Formula" of Standard Cloud Disk"
The performance of the cloud hard disk is different from that of the physical hard disk. It is
Increase as capacity grows
Of it. According to Tencent Cloud's official benchmark formula, the theoretical upper limit of a standard cloud disk is:
Random IOPS formula:$min\{1800 capacity (GiB) \times 8,\ 6000 \}$
Throughput Equation:$min\{100 Capacity (GiB) \times 0.15,\ 150 \}\ text{ MB/s}$
Since we're buying
100 GiB
, bring in the formula to calculate its "theoretical cap value":
Theoretical IOPS:$1 800 100 \times 8=2600 $
Theoretical throughput:$100 100 \times 0.15=115\text{ MB/s}$
Next, we will use FIO to actually measure it to see if it can run to this theoretical value, or if it will "drop speed" under long-term pressure measurement "!
2. Core Performance Measured: Four Scenes Bombing
In order to simulate real business scenarios (such as high concurrency of websites, database reading and writing, large file uploading, etc.), we use four standard test scripts.
Scenario 1: Core Metrics-4KiB Random Reads (Simulated Website Visits, Small File Loading)
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For most of the net
Page server, the most test of hard disk is to randomly read small files scattered everywhere.
Test command: fio -- filename =/data/testfile -- size = 5g -- direct = 1 -- rw = randread -- bs = 4k -- ioengine = libaio -- iodepth = 64 -- runtime = 120 -- numjobs = 4 -- name = rand_read_4k
Indicator
official theoretical value
Measured mean value of pressure measurement
Performance evaluation
Random read IOPS
2600
2582
Close to full marks
average delay
4 - 10ms
5.2ms
Stable in the normal range
Measured somatosensory: The IOPS curve is very smooth after the test is open for 120 seconds, and there is no cliff-like decline. 2500 + IOPS is more than enough for ordinary enterprise official websites, personal blogs or API interface services with tens of thousands of IP per day.
Scenario 2: Core Metrics-4KiB Random Write (Simulated Logging, Daily Database Modification)
Write operations typically consume more resources of the storage controller than reads.
Test command: fio -- filename =/data/testfile -- size = 5g -- direct = 1 -- rw = randwrite -- bs = 4k -- ioengine = libaio -- iodepth = 64 -- runtime = 120 -- numjobs = 4 -- name = rand_write_4k
Indicator
official theoretical value
Measured mean value of pressure measurement
Performance evaluation
Random write IOPS
2600
2495
Reach about 95% of the theoretical value
average delay
4 - 10ms
6.1ms
Occasionally slight fluctuations, but overall smooth
Measured somatosensory: When writing small files with continuous high intensity, the delay jumps to about 12ms several times, which is due to the normal physical overhead caused by the synchronous replication of the bottom three copies of distributed cloud storage. For non-ultra-high concurrent MySQL (such as general ERP and lightweight e-commerce background), this speed can be steadily brought up.
Scenario 3: large file transfer -- 256KiB sequential reading (analog picture video download, backup export)
When we want to download the big picture, video, or package and back up the whole station data on the website, we are not looking at IOPS, but throughput (Throughput).
Test command: fio -- filename =/data/testfile -- size = 5G -- direct = 1 -- rw = read -- bs = 256k -- ioengine = libaio -- iodepth =
32 --runtime=120 --numjobs=2 --name=seq_read_256k
Indicator
Official theoretical value
Average measured value from stress testing
Performance evaluation
Sequential Read Throughput
115 MB/s
114.2 MB/s
Almost perfect squeezing of clean bandwidth
Measured somatosensory: sequential reading is as stable as an old dog. The speed of 114 MB/s is equivalent to the download experience of gigabit broadband running at home. If your server is mainly used to provide file download or static resource hosting, standard cloud disk performance is quite solid.
Scenario 4: large file transfer -- 256KiB sequential writing (simulating large file upload and log dumping)
Finally, continuous writing of large files, for example, we do full system backup late at night every day.
Test command: fio -- filename =/data/testfile -- size = 5G -- direct = 1 -- rw = write -- bs = 256k -- ioengine = libaio -- iodepth = 32 -- runtime = 120 -- numjobs = 2 -- name = seq_write_256k
Indicator
Official theoretical value
Average measured value from stress testing
Performance evaluation
Sequential Write Throughput
115 MB/s
108.7 MB/s
Good performance to meet daily expectations
3. 24-hour stability test: will it be "lazy?
Most of the time, the performance of the cloud vendor's resources is full when it is first activated, but at the peak of the evening business, the performance will plummet due to the "neighbors" rushing for resources (noisy neighbor effect).
In order to verify this problem, we wrote a script that automatically ran a 10-minute 4KiB random read-write mixed test (Read/Write ratio of 7:3) every 1 hour, running for a whole day and night.
From the final derived 24-hour performance trend graph:
Maximum IOPS:2590
Minimum IOPS:2310 (occurring around 1:00 a.m., which may be the underlying host computer performing major customer backup)
Overall volatility: about 10%.
Conclusion
: Standard cloud disks have done a fairly good job of isolating and stabilizing the underlying resources, and there has been no vicious shrinkage of several hundred IOPS. Tencent Cloud's three-copy redundancy mechanism (99.9999999% data reliability) is very stable in daily stability.
4. advantages and disadvantages of objective summary
Combined with this measured data and our long-term operation and maintenance experience, the advantages and disadvantages of tengxunyun standard cloud disk can be summarized as follows:
👍flash point
Very high cost performance: Compared with the standard SSD cloud disk, the price of the standard cloud disk is much cheaper, which is very suitable for the entrepreneurial team or student party with limited budget.
Extreme performance
Close to the theoretical value: the inside story of the big factory lies in what it says and does. Whether it is IOPS or throughput, the actual measurement can squeeze more than 95% of the theoretical value.
Guaranteed for large capacity: Since performance increases linearly with capacity, if you buy a standard cloud disk with hundreds of GiB, its throughput can easily reach the hardware limit of $150\text{ MB/s}$.
👎Regret point
Weak high concurrency delay: Due to the underlying architecture, when facing hundreds of thousands of high-frequency I/O requests in an instant, its response time (Latency) will be lengthened, which is not suitable for running high-load core production databases.
The performance is low when the capacity is small: if you only buy 20 GiB and 30 GiB system disks, the IOPS is only over 2,000. If a heavy system with a lot of components is installed, it will feel a little slow when booting or updating.
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5. Selection Guide: Should You Buy It or Not?
After so many tests, I finally give you a very pragmatic landing plan. What scenario is the most cost-effective? What scenario must add money to SSD?
Scenarios suitable for selecting [standard cloud disk] (close your eyes and save money):
Personal/enterprise display official website: daily visits are not large, static pages are mostly.
Development, testing and demonstration environment: for the team to adjust the code on a daily basis, can save a lot of research and development bills.
Lightweight applications/tools: such as personal private cloud disks (Nextcloud), simple code hosting (Gitea), and various scripts that run regularly.
Pure file storage or backup disk: As the second disk of the server, it is specially used to store daily backup files.
Scenarios where you must add money to choose [General Purpose/High Performance SSD Cloud Disk] (don't save this money):
High-traffic online e-commerce and community: hundreds of people refresh and place orders at the same time every second, missing one second is a big loss.
Primary service database (MySQL / PostgreSQL): scenarios with frequent read and write operations and data latency within 1ms.
High traffic and high concurrency API interface: The IOPS of a standard cloud disk will become the barrel short board of the entire link.
One-sentence summary
: Tengxun Cloud Standard Cloud Disk is not a highly concurrent "performance monster", but it is definitely a
Duty, Honesty, Enough
The "economic long-distance runner". Just find the right positioning, it can help you save a lot of money at the same time, secure your business operation!
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