Re: Does solaris require disks to be zeroed before using

From: Beardy (beardy_at_beardy.net)
Date: 09/24/04 

Date: Fri, 24 Sep 2004 21:22:49 +0000

David A.Lethe wrote:
> On 23 Sep 2004 22:31:46 GMT, Scott Howard <scott@hunterlink.net.au>
> wrote:
>
>
>>David A.Lethe <davidATsantools.com> wrote:
>>
>>>This is causing some issues at our company, and we can't get any
>>>definitive answers. Is there any requirement, or even best-practices
>>>policies that SCSI and/or fibre channel disk drives need to have all
>>>zeros written to them before partitioning and building a file system
>>>on them?
>>
>>In a word, no.
>>
>>Solaris will never attempt to read a block of data which it hasn't
>>previously written something to.
>>
>> Scott
>
>
> Not true, and this explains the whole point of the question.
>
> Example .. .when you run the format command. Obviously it doesn't
> write before reading, or every time you ran it, it would blow the
> partitions away ;)

OK format will check for the existence of a valid label on the disk
first, and if not present, allow you to label the disk at that point.
This is an exception, and I think the OP was referring to whether data
blocks on disk should be zeroed, which they need not be; except in the
unusual case that Casper referred to.

> This brings up the reason for the question to begin with. The test
> suites don't wipe the disks clean, and we had what might have been a
> zillion-to-one shot where fdisk (on LINUX) exited with an invalid
> partition error when the sysadmin tried to partition things.

Your case is not relevant to the OP's question. The fact that the test
suites may leave patterns on the disk is still not a problem. A random
pattern and a regular pattern are identical if Solaris doesn't know they
are there.

> After I figured out problem wasn't hardware related, and using dd to
> blow the first few MB of the disk away, we have to deal with problem
> prevention ... do we adjust testing utilties to insure that all or
> part of the disk is zeroed before we let people use the disks.

Do what you feel is correct on Linux. This is not relevant to the OP's
question, and to the correct answers that have been provided to him.

Quantcast