SATA in SAS JBODs bad idea...

[ZFSLover]

Hello,

Trying to understand the summary of these:

http://hardforum.com/showthread.php?t=1548145
http://gdamore.blogspot.com/2010/08/why-sas-sata-is-not-such-great-idea.html

Is the take away that running SATA HDD"s, in a SAS JBOD connected to a SAS HBA going to cause issues?

I haven't seen this on our SMC SAS JBOD/SATA HDD setup yet on FreeNAS, anyone else here run into these issues yet?

 

[jgreco]

The summary is that hardware isn't perfect and software isn't perfect, and that you're better off avoiding SAS expanders and using SATA controllers if there's a reasonable way to do so. This is by no means a guarantee you'll have problems - lots of people are doing it without problems, from what I can tell - but it's like the choice to use ECC or non-ECC RAM. Lots of people use non-ECC RAM and don't get bit by it.

With ZFS, as counterintuitive as it is, SAS is probably the lesser choice, at least when it comes to expanders. ZFS is designed to be able to take advantage of drives in a one-drive-per-port configuration, and if you can give it a full I/O channel to each drive, your life will probably be faster and better. SAS expanders will continue to be needed for certain applications. There may be some caveats and gotchas in that scenario, in which case paying attention to experiences such as those you quote are a good idea.