SCSI or Virtio?

  • Hello All

    I have some questions regarding the feature of the product :


    Question 1:

    As default in the media driver, it is used SCSI.

    I get a very slow benchmark IO result when using this kind of driver some 43 Mb/s disks write using FIO 4k. However, when I change to Virtio driver it gets improved to > 300Mb/s.

    Question: Why is the default disk driver used after product creation using SCSI? Is it safe to use Virtio all along?


    Question 2 :

    When I upgrade the product package let's say from package 1 to package 2 on the same generation for the root server, is the upgrade deleting all the data in the disk and operating system?

    What about the additional storage that I ordered additional is it still safe when doing the upgrade?


    Question 3 :
    I have this option in the SCP setting :
    pasted-from-clipboard.png

    Please let me know what is this use for ?

    Thank you for any of your suggestion.

    • Regarding Question 1: SCSI drivers are older than their Virtio counterparts. Depending on the OS you're using, you might lack the guest drivers to use the latter. There were/are differences (from the back of my head, at least for some time, Virtio drivers lacked "TRIM" support), but as you already tested both, I'd say go with "Virtio". It's safe to use, and many customers already do so for quite some time now.
    • Regarding Question 2: Upgrades should not affect your data, although you're responsible for making use of the additional (virtual) disk space yourself (i.e., grow the existing filesystem or define a new partition). I don't use the Snapshot feature seen in the SCP, so I'm unsure whether you need to delete those before/after an upgrade in order to claim the new disk space.
      Additional storage also should not be impacted at all by an upgrade since you're still using the same KVM instance with the same IP address, therefore all previous access definitions still apply (but again, I didn't test this combination myself). Said storage is not part of your primary virtual disk, after all.
    • Regarding Question 3: This is the number of virtual sockets (see the Non-uniform memory access topic on Wikipedia). Short answer: Unless you explicitly need your system/applications to see multiple sockets, you should keep the default ("1") here in order to minimize the number of threads created by your OS.

    VServer IOPS Comparison Sheet: https://docs.google.com/spreadsheets/d/1w38zM0Bwbd4VdDCQoi1buo2I-zpwg8e0wVzFGSPh3iE/edit?usp=sharing

    3 Mal editiert, zuletzt von m_ueberall ()

    Danke 1