Feature of the LUN write through policy

4

1. After data is written to the controller, the controller needs to write the data to the disk and then feed back the acknowledgement information to the upper-layer host.
2. The reliability of data written through is increased and the performance is low.

Other related questions:
Feature of the LUN write back with mirroring policy
Write back with mirroring: Data is written to the local cache and peer cache at the same time. Write back with mirroring: features higher write performance than write through but lower write performance than write back without mirroring. This policy does not compromise the read performance. Therefore, write back with mirroring applies to the applications that require high write performance and high reliability.

Feature of the LUN write back policy
1. After data is written to the controller cache, acknowledgment information is sent to the upper-layer host, and the upper-layer host starts to write the next data. 2. The reliability of data written back is reduced and the performance is high.

Feature of the LUN write back without mirroring policy
Write back without mirroring: only writes data to the local cache. Write back without mirroring: features optimal write performance but poor reliability. Write back without mirroring applies to applications that require high write performance but low reliability.

Feature of the LUN variable prefetch policy
1. After receiving a data read request, the storage system prefetches data to the cache based on a multiple of the read length specified in the I/O request. 2. This policy applies to sequential read applications with variable-size data or to multi-user concurrent read applications with an unknown data prefetch amount, for example, multi-user Video on Demand (VOD) initiated by users at different bit rates.

Method used to modify the LUN write back policy
1. If write policy is changed to write back without mirroring or mandatory write back without mirror, the cache data in the LUN may be lost. Perform this operation with caution. 2. Go to the Modify LUN dialog box. In the ISM navigation tree, choose All Devices > SN_XX > Storage Resources > LUN (SN_XX is the name of the target storage system). In the right function pane, select the LUN you want to modify. Click Modify. The Modify LUN dialog box is displayed. Modify the basic and advanced attributes of the LUN.

If you have more questions, you can seek help from following ways:
To iKnow To Live Chat
Scroll to top