Only SATA drives that operate under SATA framework and SATA HBA drivers
have this option available to them via format -e. That''s because they
are treated and controlled by the system as scsi drives.
>From your e-mail it appears that you are talking about SATA drives
connected to legacy controllers, operating under old IDE framework and
using pci-ide/ata driver. For those drives, like for any ATA drives,
format -e does not provide read/write cache control.
Pawel
Marty Faltesek wrote:
can you answer this?
Subject:
Re: [zfs-discuss] Re: disk write cache, redux
From:
Gregory Shaw
Date:
Thu, 15 Jun 2006 21:36:52 -0600
To:
zfs-discuss@opensolaris.org
To:
zfs-discuss@opensolaris.org
I''ve got a pretty dumb question regarding SATA and write cache. I
don''t see options in ''format -e'' on SATA drives for
checking/setting
write cache.
I''ve seen the options for SCSI driver, but not SATA.
I''d like to help on the SATA write cache enable/disable problem, if I
can.
What am I missing?
Thanks!
-----
Gregory Shaw, IT Architect
Phone: (303) 673-8273 Fax: (303) 673-8273
ITCTO Group, Sun Microsystems Inc.
1 StorageTek Drive MS 4382 greg.shaw@sun.com (work)
Louisville, CO 80028-4382 shaw@fmsoft.com (home)
"When Microsoft writes an application for Linux, I''ve Won." -
Linus
Torvalds
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Pawel Wojcik wrote:> Only SATA drives that operate under SATA framework and SATA HBA drivers > have this option available to them via format -e. That''s because they > are treated and controlled by the system as scsi drives. > >From your e-mail it appears that you are talking about SATA drives > connected to legacy controllers, operating under old IDE framework and > using pci-ide/ata driver. For those drives, like for any ATA drives, > format -e does not provide read/write cache control. >hmm. well I hope sun will fix this bug, and add in the long-missing write_cache control for "regular" ata drives too.
Phil Brown wrote:> Pawel Wojcik wrote: >> Only SATA drives that operate under SATA framework and SATA HBA >> drivers have this option available to them via format -e. That''s >> because they are treated and controlled by the system as scsi drives. >> >From your e-mail it appears that you are talking about SATA drives >> connected to legacy controllers, operating under old IDE framework and >> using pci-ide/ata driver. For those drives, like for any ATA drives, >> format -e does not provide read/write cache control. >> > > > hmm. well I hope sun will fix this bug, and add in the long-missing > write_cache control for "regular" ata drives too.Actually, I believe such ata drives by default enable the write cache. Have a look at: http://cvs.opensolaris.org/source/xref/on/usr/src/uts/intel/io/dktp/controller/ata/ata_disk.c#674 (tinyurl: http://tinyurl.com/lr7jn#674) Cheers, Dana
Dana H. Myers wrote:> Phil Brown wrote: > >>hmm. well I hope sun will fix this bug, and add in the long-missing >>write_cache control for "regular" ata drives too. > > > Actually, I believe such ata drives by default enable the write cache. >some do, some dont. reguardless, the toggle functionality belongs in the ata driver as well as the scsi driver.
Dana H. Myers wrote:> Phil Brown wrote: >> Pawel Wojcik wrote: >>> Only SATA drives that operate under SATA framework and SATA HBA >>> drivers have this option available to them via format -e. That''s >>> because they are treated and controlled by the system as scsi drives. >>> >From your e-mail it appears that you are talking about SATA drives >>> connected to legacy controllers, operating under old IDE framework and >>> using pci-ide/ata driver. For those drives, like for any ATA drives, >>> format -e does not provide read/write cache control. >>> >> >> hmm. well I hope sun will fix this bug, and add in the long-missing >> write_cache control for "regular" ata drives too. > > Actually, I believe such ata drives by default enable the write cache.I could have worded this a little more clearly; what I meant to write was more like: Actually, I believe the write-cache on such ata drives is by default enabled by the ata driver (even if the drive itself defaults to disabling it).> > Have a look at: > > http://cvs.opensolaris.org/source/xref/on/usr/src/uts/intel/io/dktp/controller/ata/ata_disk.c#674 > > (tinyurl: http://tinyurl.com/lr7jn#674)