Veritas NetBackup™ Cloud Administrator's Guide

Consider the following factors when deciding the number of parallel connections:

If you increase the object size, the number of parallel connections reduce. The number of parallel connections affect the upload and download rate.

If you increase the read or write buffer size, the number of parallel connections increase. Similarly, if you want lesser number of parallel connections, you can reduce the read or write buffer size. However, you must consider the network bandwidth and the system memory availability.

Cloud providers charge for the number of PUT and GET requests that are initiated during a backup or restore process. The smaller the object size, higher the number of PUT or GET requests, and therefore, higher charges are incurred.

In case of temporary failures with data transfer, NetBackup performs multiple retries for transferring the failed objects. In such case, if the failures persist, the complete object is transferred again. Also, with higher latency and higher packet loss, the performance might reduce. To handle the latency and packet loss issues, increasing the number of parallel connections can be helpful.

NetBackup has some time-outs on the client side. If the upload operation takes more time (due to big object size) than the minimum derived NetBackup data transfer rate, there can be failures with NetBackup.

For legacy environments without deduplication support, if the number of connections are less, parallel downloads will be less compared to older number of connections.

For example, while restoring from back-level images (8.0 and earlier), where the object size is 1MB, the buffer of 16 MB (for one connection) is not completely used while also consuming memory. With the increased object size, there is a restriction on number of connections due to the available read or write buffer size memory.