Technical Announcement on Cache Defaulting to Disabled After Array Creation via Low-Version HDM on H3C Uniserver Servers

H3C G5, G6, and G7 server models (excluding PKG models)

The affected versions for each model are as follows:

When creating a RAID array on the HDM page with a supercapacitor configured, the cache mode preference remains at cache disabled, i.e., the default read policy is No Read Ahead and the default write policy is Write Through, as shown in the figure below:

To enable cache mode, customers must manually change the default read policy to Read Ahead and the default write policy to Write Back, as shown in the figure below:

After creating a RAID array on the current HDM version, the cache mode preference remains set to cache disabled (default read policy: No Read Ahead; default write policy: Write Through), which causes inconsistency between the HDM interface and the RAID controller/BIOS configuration interface in terms of default cache read/write policies. To enable cache, customers must manually adjust the settings on the HDM interface. Most customers adjust these settings based on their specific requirements.

Some customers currently need to enable cache for performance tuning. To improve operational convenience, HDM now sets the cache mode preference to cache enabled by default, eliminating the need for manual modification.

Workaround

For the affected HDM versions listed above, when creating a RAID array on the HDM page, you can enable cache by manually changing the default read policy to Read Ahead and the default write policy to Write Back.

Solution

After upgrading HDM to one of the versions listed below, cache will be enabled by default when creating a RAID array on the HDM page, without the need to manually adjust the cache policy.