Re: [PATCH] 2.4.x write barriers (updated for ext3)

[James Bottomley]

[e-mail] said:
> How do you checked it? 

I used sginfo from Doug Gilbert's sg utilities (http://www.torque.net/sg)

The version was sg3_utils-0.98

[e-mail] said:
> But when I use "scsi-config" I get under "Cache Control Page": Read
> cache enabled: Yes Write cache enabled: No 

I believe write cache enabled is the state of the WCE bit and read cache 
enabled is the inverse of the RCD bit, so you have a write through cache.

I think that notwithstanding the spec, most drives are write through (purely 
because of the safety aspect).  I suspect certain manufacturers use write back 
caching to try to improve performance figures (at the expense of safety).

James