5.13.3 Selecting the Item storage database size
Before you start using the Item storage database, you need to estimate how much disk space will be required. When estimating disk space requirements, also consider when you intend to increase the database size and rotate the storage areas.
The process of selecting the size of the Item storage database involves the following steps:
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Selecting how long you want Items to remain in the system.
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Estimating how many years of Items you want to store in the Item storage database.
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Estimating the size of the Item storage database.
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Planning future expansion of the Item storage database and rotation of the storage areas.
The procedure for planning the size of the Item storage database is described below. Note that this procedure can only provide a general estimate. The result of this process might not accurately reflect the database size in real-world use. You can track the actual capacity of the Item storage database by periodically executing the jssdbstatchk.bat (checks the database status) command.
- Organization of this subsection
(1) Setting the target lifetime for Items
As part of the Item lifecycle, you need to set the number of years (target lifetime) for which you want to store Items. In doing do, consider how many years of past Items you need to store. Because stored Items are deleted from the Item storage database at the storage area level, you need to estimate a storage area size which, together with the Item management database, is sufficient to store Items for the target lifetime.
(2) Estimating how many years of Items to store in the Item management database
The estimation method depends on whether JP1/Service Support is already in use or a new installation.
- If JP1/Service Support is already in use:
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By checking the status of an Item management database that is already in use, you can estimate how many years of Items can be stored in the database. Estimate the Item storage area and attached file storage area separately.
An example is shown below.
- Status of Item management database
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Time in operation: 1 year
Item storage area utilization: 33%
Attached file storage area utilization: 10%
- Results of estimation
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Item storage area: Approximately three years of Items can be stored in the Item management database.
Attached file storage area: Approximately 10 years of attached files can be stored in the Item management database.
- If JP1/Service Support is a new installation:
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Check the status of the Item management database after conducting a test run in which Items are registered for a sufficient period of time. This allows you to estimate the number of years of events that can be stored in the Item management database. Estimate the Item storage area and attached file storage area separately.
An example is shown below.
- Status of Item management database
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Length of test period: 1 month
Item storage area utilization: 2%
Attached file storage area utilization: 5%
- Result of estimation
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Approximately 20 months of Items can be stored in the Item management database.
You can use the jssdbstatchk.bat command to check the status of the Item management database. For details on the jssdbstatchk.bat command, see jssdbstatchk.bat (checks the database status) in Chapter 12. Commands.
(3) Estimating the size of the Item storage database
Based on the target lifetime for Items and the results of estimating the size of the Item management database in the above manner, you can now estimate the size of the Item storage database as follows:
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Estimate how many times the size of the Item storage database must be relative to the size of the Item management database.
You can calculate this information from the target lifetime for Items and the number of years of Items you wish to store in the Item management database. An example is shown below.
- Conditions
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Target Item lifetime: 8 years
Number of years of Items storable in Item management database: 3 years#
Number of years of attached files storable in Item management database: 10 years#
#: See the examples in (2) Estimating how many years of Items to store in the Item management database above.
- Results of estimation
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Items: The Item storage database must be able to store 5 years of Items. This is 1.7 times the size of the Item management database.
Attached files: The Item management database is large enough on its own to accommodate attached files for the target number of years.
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Estimate how many times you will need to expand the Item storage database.
From the results of step 1, estimate how many times you will need to expand the Item storage database. The following describes the capacity of the Item management database, and by how much the Item storage database can be expanded in one operation:
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Item storage area capacity in Item management database: Approximately 64 GB
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Attached file storage area capacity in Item management database: Approximately 28 GB
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Capacity by which Item storage area can expand in one operation: Approximately 48 GB
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Capacity by which attached file storage area can expand in one operation: Approximately 60 GB
Note that expanding the Item storage database requires 64 GB of disk space.
An example of estimating these figures is shown below.
- Item storage area
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Step 1 showed that the Item storage database must be 1.7 times the size of the Item management database.
Because the Item storage area of the Item management database is 64 GB, the size of the Item storage area must be approximately 110 GB.
Because the database can be expanded by 48 GB in a single operation, it will need to be expanded three times.
- Attached file storage area
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Per the results of step 1, the attached file storage area does not require expansion.
You can view detailed information about the capacity of the Item management database and Item storage database by using the jssdbstatchk.bat command. For details on the jssdbstatchk.bat command, see jssdbstatchk.bat (checks the database status) in Chapter 12. Commands.
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Estimate the size of the Item storage database.
Use the following formula to estimate the size of the Item storage database:
Item-storage-database-size = (64 GB x number-of-Item-storage-area-expansions# + 64 GB x number-of-attached-file-storage-area-expansions#) x number-of-storage-areas
#: Include the initial setup of the Item management database in the number of expansions.
An example is shown below.
- Results from step 2 above:
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Number of Item storage area expansions: 3 (initial setup then twice more)
Number of attached file storage area expansions: 1 (although expansion of the attached file storage area itself is not required, the initial setup of the Item storage database counts as a single expansion).
- Result of estimation:
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Results of estimating size of Item storage database = (64 GB x 3 expansions + 64 GB x 1 expansion) x 2 storage areas = 512 GB
(4) Plan the expansion and storage areas of the Item storage database
You need to plan the time frame for database expansion and rotation of the storage areas. Make these plans based on how many years of Items you want to store in the Item storage database and how many times the Item storage database needs to be expanded to accommodate these Items. An example of estimating time frames for storage area rotation is shown below.
- Time frame for expansion
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Item storage area: The Item management database (64 GB) can store approximately three years of Items. Each expansion of the Item storage database adds enough capacity to store approximately two years and three months of Items. Therefore, expanding the Item storage area every two years will suffice.
Attached file storage area: No expansion required.
- Time frame for rotation
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After expanding the database the scheduled number of times (in this case three), the storage area is rotated every five years. This is to allow further Items to be stored after a storage area has stored the number of years of Items the operator wishes to retain.