Advanced ECC with or without hot-add support

[enyamada]

I have 2 doubts about this subject:

1) I have a DL580 G4 server with 1 memory board with 4 GB. I have checked that when I set the ECC without hot-add support, the OS (Windows) sees only 3.25 GB; when I set with hot-add support, Windows can see the whole 4 GB. Is this normal? Why?

2) What is the advantage in using ECC without hot-add support?

TIA

[KarloChacon]

1. I think it's Ok because if you enable ECC the memory has to fake it
Standard ECC can correct single-bit memory errors, Advanced ECC can correct single-bit memory errors and multibit memory errors if all failed bits are on the same DRAM device on the DIMM.


2." The following rules apply to hot-add operations. Hot-add is performed by adding a memory board while the server is running, and the additional memory is made available to the operating system without a reboot.
â ¢ Boards must be inserted sequentially.
â ¢ Multiple hot-add board insertions can be performed one at a time on the same server. For example, if a server has three empty memory board slots, three hot-add board insertions can be performed.
â ¢ If multiple hot-add operations are performed, allow one board insertion operation to complete (as indicated by the memory board LEDs ("Memory board components and LEDs" on page 74) and operating system logs) before inserting another memory board"

and also

"Advanced ECC is the only mode in which hot-add operations are supported, and is the only mode in which the amount of memory available to the operating system can be increased without a reboot."

it means if you dont support hot-add you have to power off your server is case you need to increase the memory

regards

[enyamada]

Please, read my question before answering.

Thanks

[enyamada]

1) /pae option on boot.ini configuration solves the problem.
2) No idea.

[James ~ Happy Dude]

Hello,

1) As you found out; its the PAE feature.

you can refer :
http://www.microsoft.com/whdc/system/platform/server/PAE/pae_os.mspx
http://www.microsoft.com/whdc/system/platform/server/PAE/PAEdrv.mspx

2) There is NO advantage of using ECC without HOT-add Support.


* Once you disable Hot-ADD & u see 3.5GB in OS... its because of PAE;

*Once you enable HOT-ADD & you see full 4GB in OS.. its because, its BY design;
Refer page 12 of:

http://h20000.www2.hp.com/bc/docs/support/SupportManual/c00795607/c00795607.pdf

Regards,
James.