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    Disk types and SLA

    The "Disk" concept on the MCS platform is analogous to a physical storage medium such as an HDD or SSD.

    A disk is a network block device that provides data storage for instances. All disks on the MCS Platform are networked and reliably protected by data replication, ensuring storage reliability and fault tolerance.

    Benefits of network drives:

    Flexibility : Disks are independent resources, so they can be moved between instances in the same datacenter, and you can expand the size of the disk without shutting down the instance to which it is connected.

    Simplicity : Disks function as general purpose block devices, so you can think of attached drives as locally attached drives. This allows you to partition, format, and manage disks using familiar tools and techniques.

    Application : the disk is an independent element of the project and can exist separately from the instance. This is useful when you need to resize the disk regardless of the virtual machine configuration.

    Fault Tolerance : Disks provide reliable data storage and allow continuous read and write operations even if multiple physical disks fail

    Attention

    The created disk takes up space in the shared storage, so its availability is paid for separately, even if it is disconnected from the instance.

    Disc types

    Network drives differ by type and location:

    Accommodation A type Description
    ms1 HDD Basic disk located in the DataLine NORD4 data center
    dp1 HDD Basic disk located in DataPro datacenter
    ceph HDD Basic disk whose data is replicated between available data centers
    ssd SSD Standard disk whose data is replicated between available datacenters
    dp1-ssd SSD Standard disk located in DataPro data center
    ko1-ssd SSD Standard disk located in the DataLine NORD4 data center
    dp1-high-iops High-IOPS SSD Fast disk located in DataPro data center
    ko1-high-iops High-IOPS SSD Fast disk located in the DataLine NORD4 data center
    low-latency NVME Super fast disk with minimal latency (up to 0.5ms), available only on high-frequency VM configurations upon request to technical support .

    Attention

    To avoid potential performance degradation, it is recommended that you select an Availability Zone that matches your current instance when creating a disk that is attached to an existing instance.

    SLA

    For each type of disk, there is a performance limit that is required to guarantee the stability of the disk regardless of its type or size.

    HDD

    Size in GB Block size Reading Block size Recording
    IOPS MB / s IOPS MB / s
    ten 4K 300 1 4K 150 1
    64K
    nine 64K
    five
    1M
    38 1M
    19
    50 4K 300 1 4K 150 1
    64K
    nine 64K
    five
    1M
    38 1M
    19
    100 4K 300 1 4K 150 1
    64K
    nine 64K
    five
    1M
    38 1M
    19
    250 4K 300 1 4K 250 1
    64K
    nine 64K
    8
    1M
    38 1M
    31
    500 4K 500 2 4K 500 2
    64K
    sixteen 64K
    sixteen
    1M
    63 1M
    63
    1000 4K 1000 4 4K 800 3
    64K
    31 64K
    25
    1M
    125 1M
    100
    1500 4K 1500 6 4K 800 3
    64K
    47 64K
    25
    1M
    188 1M
    100
    2000 4K 2000 8 4K 800 3
    64K
    63 64K
    25
    1M
    250 1M
    100

    SSD

    Size in GB Block size Reading Block size Recording
    IOPS MB / s IOPS MB / s
    ten 4K 1000 4 4K 500 2
    64K
    31 64K
    sixteen
    1M
    125 1M
    63
    50 4K 1500 6 4K 750 3
    64K
    47 64K
    23
    1M
    188 1M
    94
    100 4K 3000 12 4K 1500 6
    64K
    94 64K
    47
    1M
    375 1M
    188
    250 4K 7500 29 4K 3750 fifteen
    64K
    234 64K
    117
    1M
    400 1M
    400
    500 4K 15000 59 4K 7500 29
    64K
    400 64K
    234
    1M
    400 1M
    400
    1000 4K 16000 63 4K 8000 31
    64K
    400 64K
    250
    1M
    400 1M
    400
    1500 4K 16000 63 4K 8000 31
    64K
    400 64K
    250
    1M
    400 1M
    400
    2000 4K 16000 63 4K 8000 31
    64K
    400 64K
    250
    1M
    400 1M
    400

    High-IOPS SSD

    Size in GB Block size Reading Block size Recording
    IOPS MB / s IOPS MB / s
    ten 4K 10000 39 4K 5000 20
    64K
    313 64K
    156
    1M
    500 1M
    500
    50 4K 10000 39 4K 5000 20
    64K
    313 64K
    156
    1M
    500 1M
    500
    100 4K 10000 39 4K 5000 20
    64K
    313 64K
    156
    1M
    500 1M
    500
    250 4K 10000 39 4K 6250 24
    64K
    313 64K
    195
    1M
    500 1M
    500
    500 4K 15000 59 4K 12500 49
    64K
    469 64K
    391
    1M
    500 1M
    500
    1000 4K 30,000 117 4K 25000 98
    64K
    500 64K
    500
    1M
    500 1M
    500
    1500 4K 45000 176 4K 30,000 117
    64K
    500 64K
    500
    1M
    500 1M
    500
    2000 4K 45000 176 4K 30,000 117
    64K
    500 64K
    500
    1M
    500 1M
    500

    Low latency

    Size in GB Block size Reading Block size Recording
    IOPS MB / s IOPS MB / s
    ten 4K 1000 4 4K 500 2
    64K 31 64K sixteen
    1M 125 1M 63
    50 4K 1500 6 4K 750 3
    64K 47 64K 23
    1M 188 1M 94
    100 4K 3000 12 4K 1500 6
    64K 94 64K 47
    1M 375 1M 188
    250 4K 7500 29 4K 3750 fifteen
    64K 234 64K 117
    1M 400 1M 400
    500 4K 15000 59 4K 7500 29
    64K 400 64K 234
    1M 400 1M 400
    1000 4K 16000 63 4K 8000 31
    64K 400 64K 250
    1M 400 1M 400
    1500 4K 16000 63 4K 8000 31
    64K 400 64K 250
    1M 400 1M 400
    2000 4K 16000 63 4K 8000 31
    64K 400 64K 250
    1M 400 1M 400

    Note

    Disk performance directly depends on its size. If you need to increase the processing speed, sometimes it is enough to increase the size of the required disk.

    How to test

    For Windows

    You can use DiskSPD or Fio software to measure read / write IOPS.

    DiskSPD

    DiskPSD is an official testing tool recommended by Microsoft and included in the developer repositories . The following steps are required to complete testing:

    1. Download the utility from the official resource and unpack it to a convenient place: https://github.com/microsoft/diskspd/releases/latest
    2. Run command line as administrator and go to the directory with the unpacked utility DiskSpd-2.0.21a \ amd64 \
    3. Pre-create an empty file with a size of at least 10GB:
       fsutil file createnew C: \ temp \ test.bin 10485760000
    4. To execute tests, you must use the command corresponding to the test type:
    • Random Write Test:
     diskspd -Suw -b4K -o1 -t32 -r -w100 C: \ temp \ test.bin> C: \ temp \ random_write_results.txt
    • Random read test:
     diskspd -Suw -b4K -o1 -t32 -r -w0 C: \ temp \ test.bin> C: \ temp \ random_read_results.txt

    Fio

    IOPS measurements using fio are performed using the rate_iops parameter. Tests are performed with values:

    • --rw (randread or randwrite)
    • --filename (name of the device under test)
    • --iodepth (8, 16, 32 or 64)

    Download and install Fio from the official resource: https://bsdio.com/fio/

    Command to run the test:

     fio --name = randwrite --iodepth = 32 --rw = randwrite --bs = 4k --direct = 1 --size = 10G --numjobs = 1 --runtime = 240 --group_reporting --filename = C: \ Users \ ADMIN \ test

    Note

    The mechanics of Fio are different from the DiskSPD tool. The Fio records in 2 files, so the measurement results may be different for both instruments. Nevertheless, Microsoft Corporation trusts its tool and recommends using DiskSPD on Windows operating systems.

    For Linux

    The read / write IOPS measurements are performed by the fio software and the rate_iops parameter. Tests are performed with values:

    • --rw (randread or randwrite)
    • --filename (name of the device under test)
    • --iodepth (8, 16, 32 or 64)

    Installing Fio:

     sudo apt install fio

    Command to run the test:

     fio --name = randwrite --ioengine = libaio --iodepth = 32 --rw = randwrite --bs = 4k --direct = 1 --size = 512M --numjobs = 1 --runtime = 240 --group_reporting - -filename = / home / user / test

    Measurement results:

    • read: IOPS
    • write: IOPS
    Types of testing performed Test result (Number of IOPS)
    Read / Write in 4 KB blocks in 32 threads According to SLA values
    Read / Write in 8 KB blocks in 32 threads at least 75% of the SLA
    Read / Write 16KB in 32 Streams at least 50% of the SLA


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