I am working on the project to develop a custom application (developed in C++, using Centera SDK 3.2 Patch  5) that will be used for archiving of new and migration of the existing documents from optical storage to Centera storage appliance.

Each document consists of two files that are saved in one Centera Clip as two separate BLOBs. The application is using the EMBEDDING threshold of 100 K.

Majority of the files (75%) are less than 100K. The file size is rarely larger than 1 MB.

EBR and static retention classes are assigned to each new created Clip.

If the document already exists in Centera, the application opens the existing clip, replaces the existing two blobs and writes the clip back (saving the new C-clip).

Target Centera consists of two clusters with bidirectional replication. Cluster version is Gen4 CE+ (Compliance Edition Plus). CentraStar OS version is 4.02.

The module that writes to Centera is a separate thread. The application can start configurable number of these threads.

At this point we are noticing that storing files to Centera is the bottleneck. We can not get better throughput than about 5 to 10 documents per second (10 to 20 files per second) no matter how many threads are used.

Below are the current performance results.

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Num of   New Clip Write  Existing Clip Write

threads  (files/sec)     (files/sec)

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1         9               6

2        15              11

5        19              12

10       21              14

20       24              15

--------------------------------------------------------

Document per second speed is 1/2 of Files/second

Here are my questions:

1. Is above mentioned archiving speed considered normal? What is the expected archiving speed for the file size sample I described above (75% files sizes in the range of 2K to 100K, 25% 100K to 1MB)?

2. Why is there a considerable difference in speed when writing to an existing clip (re-writing existing clip is slower)?

3. Can you provide more details or point me to the resources that describe the methods to optimize the archiving performance.

We followed the recommendations from the SDK documentation. I understand that the questions might be a bit too general but any help would be greatly appreciated.