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Deleting Database Log Files
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Last modified on 7/14/2014 2:11 PM by User.

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Deleting Database Log Files

 

Overview

From time to time, we receive calls from OASIS users asking if it would “ok” to delete log files for OASIS. In some cases, the issue is real as the server is running low on disc space. This document describes the best way to manage this case.

Running Low on Disc Space!

The problem is real for some of our users. The features in OASIS have proven to be extremely valuable to many OASIS users – especially submittals and the attachments features. Unfortunately, these features use a lot of disc space. As of this writing, the largest OASIS database is just over 100GB is size. To some this sounds like a lot of disc space. However, this is the standard hard drive size for many computers these days!

Before running out and upgrading a server, review the minimum disc size requirements defined below and consider the purchase of a low cost USB hard drive.

The Sybase Database

OASIS uses a product from Sybase named Adaptive Server Anywhere (ASA). ASA is known as a relational database and implements an internal recovery technology. The advantage is that for most system failures, the database automatically recovers. The down side is that the recovery process uses disc space for a “log file”. So what are the files utilized by the OASIS database?


 

oasis.db  - this IS the OASIS database. All the POs, Quotes, attachments and much more!

oasis.log – this is the active log (recovery) file

YYNNNNAA.LOG – these are inactive recovery files.

How does the system work? In short, when you open view an order in OASIS, the data is pulled from oasis.db. When you save an order (or other transaction) in OASIS, the data is written to both oasis.db and oasis.log. This “dual write” is important when there is a system failure (e.g. the server loses power) as if the data in one of the files (most likely oasis.db) is clobbered, the oasis.log file is automatically “consulted” by the database to correct the error. Pretty cool!

The down side is that the size of the oasis.log file will grow forever and it should be truncated (rotated for you database administrators out there) periodically. THIS DOES NOT MEAN DELETE. Deleting the oasis.log file will likely cause your database not to start. However, if you login to OASIS, select “Software” under “Configuration” and click on “Backup transaction log”:


 

The database will take the following actions:

  1. The oasis.log file is renamed using the date and some unique letters (e.g. 090106AA.LOG)
  2. A new (empty) oasis.log file is created

What CAN I Delete?!

The official answer from Ingen Software is: NOTHING! Ok, that is a little harsh, but before giving a better answer to the question, you must understand that we have helped several groups recover data from a mechanical hard drive failure, power outages, server faults, virus invasions and we have even seen a “bullet proof” raid 5 array crash. But we have never lost an entire database – yet, and we DO NOT want YOU to be the first. Consider this:

With all the log files created for the OASIS database, it is possible to recover from a hardware failure and rebuild the database to the moment of failure!
And we have done this several times already (that should scare you).

Here is the official recommendation to recover space on a server due to large or numerous oasis.log files:

  1. Use the method above to backup the transaction log
  2. Stop the OASIS database
  3. Purchase an external USB hard drive (cost today is about $100 for 100GB USB drive - $300 for 1TB or 1000GB!)
  4. Copy ALL  files in the oasis database directory to the USB drive AND VERIFY THE FILES DID COPY.
  5. Remove all files from the OASIS database directory formatted with six numbers, two letters and having the extension .log
  6. DO NOT DELETE oasis.db or oasis.log – NEVER
  7. Start the database and verify transactions from the previous day (ensures the data is still on the server).
  8. Place the USB drive in a bank Safe deposit box

If this sounds like a lot, then consider this: what if all the data you have in OASIS right now were to simply disappear right now? Would your business be negatively impacted?

What are the MINIMUM OASIS Hard Drive Requirements?

The OASIS database is a dynamic file cabinet and the drive requirements vary greatly between OASIS users. New users should assume 10GB of disc usage the first year. Likely MORE if going “green” by using OASIS for document management.

When “cleaning up” as server using the process above, the smallest the database will ever be is 1.5 times the size of the oasis.db file. The .5 estimate is for:

  • The required oasis.log file
  • Temporary files created by the database

Do realize, this is the bare minimum.