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RE: High disk capacity dangers

From: Khemmanivanh, Somckit <>
Date: Tue, 6 Jun 2006 10:28:07 -0700
Message-ID: <65C0D8935651CB4D96E97CEFAC5A12B9022F13DC@wafedixm10.corp.weyer.pri>

You are using online JFS correct? Then it's not that big of a concern.

Here's something from HP's Engineer's on the subject:

· I have been assured by several engineers that OnlineJFS will NOT corrupt data as the file system fills up
· The file system may begin to report failed writes due to lack of space (more relevant on a typical file system where new files are constantly being created)

· The Admin Guide suggests keeping a minimum of 10% free for an JFS file system
· The available storage is equal to the requested/configured. Additional storage for the metadata of OnlineJFS is added outside of the configured storage. The amount of space allocated for metadata is a percentage of the configured storage so varies by capacity

· File systems can be extended online or offline, depending on underlying physical storage.
· File system extension WILL NOT cause data corruption
· File system extension could have problems IF the file system is excessively full
· VxVM can extend the volume online
· OnlineJFS can extend the file system after one of the above volume extensions is performed, online
· There are a number of performance and tuning commands available for OnlineJFS. Please refer to the Administration Guide.

-----Original Message-----
From: [] On Behalf Of Jesper Haure Norrevang Sent: Tuesday, June 06, 2006 6:25 AM
To:; Subject: SV: High disk capacity dangers


In my shop we have 40 databases on HP-UX. I have dedicated file systems for the Oracle databases. I see no problem in filling them 99 %, as long as no datafiles are running in AUTOEXTEND mode.

I usually reserve a little space for the control files to grow. Yes I want them to grow, because I have set CONTROL_FILE_RECORD_KEEP_TIME = 30 in order to keep information about RMAN-backup in the control file for one month, if I should be unlucky and loose my recovery catalog.

Many years ago I had a case on Digital Unix/SAP R3 with tar making sparse files when restoring datafiles from tape. It was dangerous, when the datafiles started to grow physically as new blocks were formatted, but it is quite another story.

Jesper Norrevang

-----Oprindelig meddelelse-----
Fra: [] På vegne af Fred Smith
Sendt: 6. juni 2006 14:05
Emne: High disk capacity dangers

Just wanted to run this by everyone here, I have a database on HP-UX. Some of my read only tablespaces are on a physical disk that I keep at about 99% capacity (it's not going to grow obviously, it's read-only). The new Unix SA is saying that it's unacceptable and dangerous to keep a disk at 98,99, or 100% capacity. I always thought it could be even at 100% capacity without any problems.

Is there any reason that anyone knows of as to why a disk should not be at 99% or 100% capacity?

Thank you!

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Received on Tue Jun 06 2006 - 12:28:07 CDT

Original text of this message