RE: datafile permissions
- From: "Khemmanivanh, Somckit" <somckit.khemmanivanh@xxxxxxxxxxxxxxxx>
- To: <all_about_oracle@xxxxxxxxxx>, <raja4list@xxxxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
- Date: Tue, 5 Jul 2005 22:30:54 -0700
Not to harp on this too much but I'm really failing to see how this is
such a risky task? He's going from mode 600 to 640.
You can run this test yourself to see that there shouldn't be any issues
with doing this.
1) create a test file
rm skf
touch skf
chmod 600 skf
ll skf
-rw------- 0 Jul 5 22:16 skf
2) As a control run the supplied C program I whipped up to test. All it
does is open the file and write a bunch text to it
It will create a file exactly 99999999 bytes in size
ll skf
-rw------- 99999999 Jul 5 22:17 skf
Below is the code (compile and run it)
#include <stdio.h>
int main ()
{
FILE * myf;
int counter = 0;
myf = fopen ("skf","wt");
if (myf != NULL)
{
while ( counter < 99999999)
{
fputs ("t", myf);
counter++;
}
}
}
3) Delete the skf file and recreate it with mode 600 for the run with
the chmod in it.
--Run the program in 1 session and in another session run the following
commands.
ll skf; chmod 640 skf; ll skf
-rw------- 6062080 Jul 5 22:18 skf
^^^--Note the mode is 600 from the first ll skf commnd
-rw-r----- 6193152 Jul 5 22:18 skf
^^^--Note the mode has changed to 640 with the chmod comand (this while
the other program is still writing to the file)
4) Now recheck the file after it's all complete.
ll skf
-rw-r----- 99999999 Jul 5 22:19 skf
Does anyone see any flaws with this test???
Thanks!
________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Sinardy
Sent: Tuesday, July 05, 2005 9:31 PM
To: raja4list@xxxxxxxxx; oracle-l@xxxxxxxxxxxxx
Subject: Re: datafile permissions
If someone is writing to the file then you revoke the access using OS
command which is it can be done with Unix I believe your manager forsee
this will corrupt the datafile.
Anyway, if I am asked to perform such harderning change, I will request
for down time. For may be 1 hour, stop applications, shutdown, chmod,
startup, switch log file, test, star application. not only datafile
offline.
PS: I know that 640 should be ok but chmod during online is quite a
risky task.
Regards,
Sinardy
----- Original Message -----
From: raja rao <mailto:raja4list@xxxxxxxxx>
To: oracle-l@xxxxxxxxxxxxx
Sent: Wednesday, July 06, 2005 5:19 AM
Subject: datafile permissions
Hi All,
Sun OS 2.9
oracle 9i
In what state the datafiles should be when i want to change the
OS file permissions
from 600 to 640
chmod 640 *.dbf
I put the tablespace offline. is that enough?, or should i make
the datafiles offline withi
alter database datafile 'filename' offline;
I had a fight with my manager. He asked me to put the datafiles
offline using alter database.
But Just i put the tablespace offline and did that. Just want to
make sure what is
the right way (precautiion to be taken) for this task ?
Thanks in advance,
Raj
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