Greg Smith escribió:
> On Sat, 1 Dec 2007, Tomasz Ostrowski wrote:
>
>> You can also use "hdparm -I" to check this - look for a "Write
>> caching" in "Commands/features" section. If it has a "*" in front
>> then it is enabled and dangerous.
>
> Right; using -I works with most Linux hdparm versions:
>
> # hdparm -V
> hdparm v6.6
> # hdparm -I /dev/hda | grep "Write cache"
> * Write cache
> # hdparm -W 0 /dev/hda
>
> /dev/hda:
> setting drive write-caching to 0 (off)
> # hdparm -I /dev/hda | grep "Write cache"
> Write cache
Out of ignorance, do RAID[1] devices have write cache?
[1]: I'm talking about RAID through hardware.
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TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
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