32 bit or 64 bit ?

[HSW Support]

We will be looking to replace some servers soon but I'm a bit confused over the 32/64 bit choice. Are systems are relatively small (currently use D series etc, 20Gb max disk usage etc) and are unlikely to get much bigger.

Questions are :

1. What advantage would 64 bit machines give me
2. Can I run existing 32 bit applications on 64 bit architecture
3. Is 64 bit the future. Do you think that HP etc will try to move away from 32 bit architecture in the nearish future.

Any other comments most welcome.

Cheers

Mike

[Sanjay_6 · Accepted solution]

Hi Mike,

Take a look at this faq,

http://devresource.hp.com/STK/hpux_faq.html

For more info look at the hp devresource web site in the address above.

Hope this helps.

Regds

[A. Clay Stephenson]

Hi Mike:

The only advantage is larger address space and larger file addressing. Shared memory can be much larger and well as maxdsiz in 64-bit land.
You will not see performance improvements by going to 64-bit HP-UX.

With very few exceptions, 32-bit applications will run in 64-bit land. Applications which are kernel intrusive (like lsof) will fail; however, almost all applications (10.20 & up) will run without problems. One gotcha is shared memory segments between 64-bit processes and 32-bit processes; it can be done but the applications programmer has to plan for it in advance.

I would have to say that 64-bit is the future - if for no other reason than marketing but I don't see 32-bit dropped until your D-boxes are considered so old and slow that your question becomes moot.

One more point, if you do choose 64-bit on your D-boxes you must throw away all your EISA cards.

My 3 cents, Clay

[Sridhar Bhaskarla]

Hi Mike,

Check these sites. You can decide on your own after reading them

http://dsportal.eservices.hp.com/dspp/tech/tech_TechDocumentDetailPage_IDX/1,1701,937,00.html

http://dsportal.eservices.hp.com/dspp/tech/tech_TechDocumentDetailPage_IDX/1,1701,989,00.html

-Sri

[Roger Baptiste]

1. What advantage would 64 bit machines give me

>> Can use 64-bit applications; address more memory, dataspace, shared memory etc.

2. Can I run existing 32 bit applications on 64 bit architecture

>> Yes. Which is an advantage.

3. Is 64 bit the future.

>> yes.

Do you think that HP etc will try to move away from 32 bit architecture in the nearish future.

>> We can only speculate, but since i dont see any disadvantage in installing 64-bit, i would prefer to install 64-bit over a 32-bit.

-raj

[ian Dennison]

Just a small note that delayed our 32-64 bit upgrade,...

Given the larger address space available to OS and Applications, our Application Vendor insisted on an obscene amount of swap (minimum 20GB) being available on the system before upgrading to the 64 bit version of SAP. What resources does your vendor require for 64 bit?

64 bit is the way of the future, but can take some additional resources on the system to get it in!

Hope this is of some help. Fred

[Deshpande Prashant]

HI
I do not think with HPUX 11.x 64 bit you need double the swap as RAM, as you can turn the sudo swap (swapmem_on) on.
What is the amount of memory you are looking for your new servers?

Prashant.

[Eileen Millen]

The D system might be able to do 64 bit word.
There is a list on the HP website.
The firmware may have to be upgraded.

Eileen