Re: Major Linux performance regression; shouldn't we be worried about RHEL6?

On Nov 5, 2010, at 1:19 PM, Josh Berkus wrote:

>
>> The serious problems with this appear to be (a) that Linux/Ext4 PG
>> performance still hasn't fully recovered, and, (b) that RHEL6 is set to
>> ship with kernel 2.6.32, which means that we'll have a whole generation
>> of RHEL which is off-limits to PostgreSQL.
>
> Oh. Found some other information on the issue. Looks like the problem
> is fixed in later kernels. So the only real issue is: is RHEL6 shipping
> with 2.6.32?
>

No, RHEL 6 is not on any specific upstream Kernel version. Its 2.6.32++, with many changes from .33 to .35 also in there. You can probably assume that ALL ext4 changes are in there (since RedHat develops and contributes that). Plus, it will have several features that RedHat has not gotten pushed upstream completely yet, such as the automatic huge pages stuff.

The likelihood that file system related fixes from the .33 to .35 range did not make RHEL 6 is very low.

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