On Nov 12, 2011, at 8:31 AM, Pasi Kärkkäinen wrote:

> On Sat, Nov 12, 2011 at 08:15:31AM -0500, David Magda wrote:
>> On Nov 12, 2011, at 00:55, Richard Elling wrote:
>>> Better than ?
>>> If the disks advertise 512 bytes, the only way around it is with a 
>>> whitelist. I would
>>> be rather surprised if Oracle sells 4KB sector disks for Solaris systems?
>> Solaris 10. OpenSolaris.
>> But would it be surprising to use SANs with Solaris? Or perhaps run Solaris 
>> under some kind of virtualized environment where the virtual disk has a 
>> particular block size? Or maybe SSDs, which tend to read/write/delete in 
>> certain block sizes?
>> In these situations simply assuming 512 may slow things down.
>> And if Solaris 11 is going to be around for a decade or so, I'd hazard to 
>> guess that 512B sector disks will become less and less prevalent as time 
>> goes on. Might as well enable the functionality now, when 4K is rarer, so 
>> you have more time to test and tunes things out?rather than later when you 
>> can potentially be left scrambling.
>> As Pasi Kärkkäinen mentions, there's not much you can do if the disks lies 
>> (just as has been seen with disks that lie about flushing the cache). This 
>> is mostly a temporary kludge for legacy's sake. More and more disks will be 
>> truthful as times goes on.
> Most "4kB"/sector disks already today properly report both the physical (4kB) 
> and logical (512b) sector sizes.
> It sounds like *solaris is only checking the logical (512b) sector size, not 
> the physical (4kB) sector size..

ZFS uses the physical block size.

 -- richard


ZFS and performance consulting
LISA '11, Boston, MA, December 4-9 

zfs-discuss mailing list

Reply via email to