# even dumber AMD64 questions



## dave (Mar 28, 2011)

I read everywhere that AMD64 is better for use with ZFS.  Does this exclude Intel 64-bit hardware?  Or does this refer to both Intel and AMD 64-bit systems?

Wikipedia Says...


> BSD systems such as FreeBSD, MidnightBSD, NetBSD and OpenBSD refer to both AMD64 and Intel 64 under the architecture name "amd64".



Is that true for the purposes of ZFS tuning?

Thanks...


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## Terry_Kennedy (Mar 28, 2011)

dave said:
			
		

> I read everywhere that AMD64 is better for use with ZFS.  Does this exclude Intel 64-bit hardware?  Or does this refer to both Intel and AMD 64-bit systems?


AMD released CPUs with 64-bit extensions to the i86 architecture first. Intel was busy with the Itanium, which was a 64-bit CPU with a completely different architecture. Eventually, they noticed that AMD was selling a lot of 64-bit CPUs. [As an aside, in a "good year", several thousand Itanium systems are sold - compared with millions of systems with x86 and amd64 chips].

Anyway, since AMD got there first, the architecture was referred to as "amd64" by some (including FreeBSD). That's the case even when running on an Intel CPU that implements (mostly) that same instruction set. Microsoft refers this as "x64", which confuses things. I guess they didn't want to offend Intel by calling it "Windows 7 amd64 Edition".

The Itanium CPU and architecture are referred to as "IA64" or sometimes "IA-64". 



> Is that true for the purposes of ZFS tuning?


Yes - you want to run FreeBSD with the amd64 architecture, assuming you have an AMD or Intel CPU that supports it. amd64 lets you address memory above 4GB, while the x86 architecture relies on a hack (PAE) to address more than 4GB. Not all drivers (regardless of operating system - Windows has the same issue) are "PAE-clean" and can run into problems due to transferring data to the wrong place in memory. Work on making drivers PAE-clean has pretty much stopped now that the amd64 architecture is well-supported.

In any event, ZFS runs faster with more memory available to it, and amd64 gets you that memory. Use amd64 if your CPU supports it.


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## phoenix (Mar 28, 2011)

Searching the forums for "amd64" and "intel" (and even "zfs") would bring up many, many, many threads on this very popular subject.  This question gets asked at least once a month, if not more often.

There is a reason for that fancy "Search" link at the top of every page.


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## zennybsd (Mar 31, 2011)

This link (http://wiki.freebsd.org/ZFSTuningGuide) could be helpful if you want to use zfs with some tuning in 32-bit processors. 

***If my reply helped you, don't forget to visit this link***


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## dave (Mar 31, 2011)

zennybsd said:
			
		

> This link (http://wiki.freebsd.org/ZFSTuningGuide) could be helpful if you want to use zfs with some tuning in 32-bit processors.
> 
> ***If my reply helped you, don't forget to visit this link***



Believe me, I have read the tuning guide.  That's why I am looking into 64-bit hardware.  First I had an unstable machine, then I tuned it so it would not constantly reboot, and now whenever I put a load on my ZFS array, the drive checksums start to climb, and I get the error message "One or more devices has experienced an unrecoverable error...".


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## dave (Mar 31, 2011)

phoenix said:
			
		

> Searching the forums for "amd64" and "intel" (and even "zfs") would bring up many, many, many threads on this very popular subject.  This question gets asked at least once a month, if not more often.
> 
> There is a reason for that fancy "Search" link at the top of every page.



This may be true.  I am familiar with the strategy of search for finding information on a particular topic.  But after searching, I did not see any relevant thread titles for my specific question.   I don't have time to wade through all that other stuff, so I thought I would put the question out there.


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## zennybsd (Mar 31, 2011)

dave said:
			
		

> Believe me, I have read the tuning guide.  That's why I am looking into 64-bit hardware.  First I had an unstable machine, then I tuned it so it would not constantly reboot, and now whenever I put a load on my ZFS array, the drive checksums start to climb, and I get the error message "One or more devices has experienced an unrecoverable error...".



1. Did you try exporting (importing) the zpool(s) to check whether the problem is due to the zfs?  

For the relevant documentation, visit http://docs.huihoo.com/opensolaris/solaris-zfs-administration-guide/html/ch04s06.html

2. Do you have 'advanced format drives'? If yes, did you turn it off before creating the zpool? 

If not, this link may help:  http://forums.freebsd.org/showthread.php?t=21644

Hope you may solve your problem. ;-)


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## dave (Jun 14, 2011)

To follow up on this, I should mention that I replaced the power supply on the machine with a 650W and the ZFS issues have not surfaced again.  I am continuing to research hardware for a new VFS file server.


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## SirDice (Jun 16, 2011)

Yeah, these days you need a really powerful PSU. Depending on how many disks you have and how powerful your videocard is even 650W might not be enough. Bigger is better in this case :e


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