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Cloud Storage Gateway:Manage a cache disk

Last Updated:Dec 08, 2023

This topic describes how to manage a cache disk in the Cloud Storage Gateway (CSG) console. For example, you can attach or scale out a cache disk.

Prerequisites

An iSCSI gateway is created. For more information, see Create an iSCSI gateway.

Background information

Currently, iSCSI volumes support the Cache and Write Through modes. You can select a cache disk for each iSCSI volume that has the Cache mode enabled. The Cache mode allows read and write operations to use local cache disks first. If you need to create an iSCSI volume that has the Cache mode enabled, you must add a cache disk to the iSCSI gateway first.

Note

Methods introduced in this topic apply only to cache disk management of iSCSI gateways deployed in Alibaba Cloud. If you want to add a cache disk for an on-premises iSCSI gateway, you must add a cache disk on the on-premises console. For more information, see Add disks.

Add a cache disk

  1. Log on to the CSG console.

  2. Select the region where the iSCSI gateway resides.

  3. In the left-side navigation pane, click Gateways. On the page that appears, click the iSCSI gateway ID to open the Volumes page.

  4. In the left-side navigation pane, click Cache. On the Cache page, click Create Cache.

  5. In the Add Cache dialog box, configure the following parameters:

    • Capacity: the size of the cache disk. Valid values: 20 GB to 32 TB.

    • Type: the type of the cache disk. Valid values: Ultra Disk, Standard SSD, and ESSD.

    Note
    • The maximum cache capacity for a Basic gateway is 1 TB. ESSD PL3 is not supported for Basic gateways.

    • The maximum cache capacity for a Standard gateway is 2 TB.

  6. Click OK.

    If the iSCSI gateway is a subscription gateway, you are redirected to the cache disk buy page. For more information, see Purchase a cache disk.

Scale out a cache disk

You can increase the cache capacity for iSCSI gateways.

Warning

Note: After you expand a cache disk, the gateway automatically restarts. Do not perform any operation on the gateway during this process.

  1. On the Cache page, find the cache disk and click the plus sign (+) in the Actions column.

  2. In the Scale Up Cache dialog box, set the new size of the cache disk, and then click OK.

    Note
    • You are not allowed to expand a cache disk to a size larger than 6 TB. If you need a cache disk larger than 6 TB, you have to add a new cache disk.

    • You cannot scale down a cache disk.

    If you expand the cache capacity of a subscription iSCSI gateway, you are redirected to the cache disk buy page after you click OK. On the cache disk buy page, change the cache capacity to the expected size and complete the payment. Cache scaling is automatically performed after you complete the payment.

    For example, if the current cache disk is an ESSD PL1 cache disk and you want to increase the cache capacity from100 GB to 200 GB, change the cache capacity of the ESSD PL1 cache disk to 200 GB and complete the payment.

What to do next

Create an iSCSI volume