This message is from the T13 list server.
Nathan: Not to be rude, but what reflector are you mailing. I made a friendly proposal/ammendment to FUA to enable forced write ordered events. It got rejected, period. The reason was MicroSoft deemed it all important to jump the queue. Now to clear the point. Add to FUA the option to force ordering where as sane and proper filesystems can trust their host driver will be in control of FUA operations. I do not care how or why MicroSoft needs or wants this feature; however, to rudely refuse ammendments to assist the acceptance will yeild toasty discussions. Grant the addition of one bit in the features register when FUA is enabled to allow and forced ordered behavior. You are quoting T10, but the behavior the device is not that of T10. So if FUA is going to have a chance and not earn the label of "DATA CORRUPTION FEATURE", introduced by MicroSoft, consider adjusting the stance and work with the concerns of your peers. 800 pound gorillas face mortality when the elephant gun arrives. Nothing personal, all technical. Cheers, Andre Hedrick LAD Storage Consulting Group On Thu, 26 Jun 2003, Nathan Obr wrote: > This message is from the T13 list server. > > > I am sending this as a test. I haven't been able to get onto the T13 > List Server yet although I have been trying to reply to this thread for > a while. I apologize if I reawaken the issue. For those who were not > at the T13 meeting this week, the original issue has been resolved and > hopefully the below clarification will resolve any outstanding ones. > ------------------------ > > [My original, long delayed email] > Everyone has made far too big of a deal out of this. First off, FUA > doesn't affect queuing or write ordering. The only difference between > FUA I/O and other types of I/O is that FUA has the added restriction > that the data must be to the medium before the drive can say the > transaction is complete. That's it. The drive may still queue the > command and handle it however it sees fit. It seems like there should > be more to it, but there isn't. > > Hopefully, you can see that there is no need for concern over overlapped > LBA or affects on the queue as it doesn't affect write ordering or the > queue. > > By the way, before too many people decide to jump ship for T10, you will > be interested to know that SCSI has had support for FUA for quite some > time (See SBC). Many hard drive manufacturers shouldn't have a problem > implementing this as much of it can be borrowed from their existing SCSI > lines. > > Nathan > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of > Curtis Stevens > Sent: Monday, June 23, 2003 7:39 PM > To: T13 List Server > Subject: Re: [t13] hmmm.. no comments? > > This message is from the T13 list server. > > > Gary > > The wording you propose would defeat the purpose of the command. I > do > not know if you were there for the discussion. The purpose of the FUA > was > to cause critical data to be committed to the media, regardless of what > is > in the que. If you wait for a flush you are delaying the higher > priority > data. Furthermore, If you know that the area you are writing is for > this > type of critical data you can prevent the issue you are trying to solve > in > the drive... Queued FUA is not a function for everyday use, but if you > use > it for the purpose intended it has great value. Fir instance, if power > has > been removed from the system and you only have a few MS to store the > state, > you would wrather not wait for the que to execute or flush, nor would > you > want to go through the very time consuming process of aborting the que. > You > simply was the state information committed in the shortest possible > time. I > see this as one of the main uses for queued FUA commands. > > --------------------------- > Curtis E. Stevens > 29 Dewey > Irvine, Ca 92620 > > Home: (949) 552-4777 > E-Mail: [EMAIL PROTECTED] > > The face of a child can say it all, especially the mouth part of the > face... > ----- Original Message ----- > From: "Gary Laatsch" <[EMAIL PROTECTED]> > To: "Curtis Stevens" <[EMAIL PROTECTED]>; "T13 List Server" > <[EMAIL PROTECTED]> > Sent: Monday, June 23, 2003 2:40 PM > Subject: Re: [t13] hmmm.. no comments? > > > > Curtis, > > > > Dropping HDD's is one of those very unsafe thing to do :-) > > > > My 2 cents on the whole deal is simple. Mark Vallis brought up a very > good > > point in his example of 2 read requests and the 1 write request in the > queue > > and than overlapped by a FUA Write request. The current ATAPI-7 spec > > indicates that the FUA command shall not be released. Obviously if > you do > > this, the result is the read data returned is in question (return the > old > or > > new data, the command was recieved before but processed after). Also, > the > > queued write would request data that should be older then the data > just > > written with the FUA since the command was actually recieved before. > I > > think this is really an exception case and should be handled as such. > > > > My opinion is to modify the wording to the queued FUA commands to add > > something like "if the queued FUA request overlaps a previously queued > > command, that the queue shall be flushed....blah blah blah" or however > we > > say it in T13 queue-ish. The biggest issue is that in this case, the > FUA > > needs to release and it slows down because of the clean up needed to > insure > > data integrity. But I know that you guys will figure it out this week > up > > there in SJ. Have fun. > > > > Gary Laatsch > > [EMAIL PROTECTED] > > > > ----- Original Message ----- > > From: "Curtis Stevens" <[EMAIL PROTECTED]> > > To: "T13 List Server" <[EMAIL PROTECTED]> > > Sent: Monday, June 23, 2003 10:20 AM > > Subject: Re: [t13] hmmm.. no comments? > > > > > > > This message is from the T13 list server. > > > > > > > > > I really don't think the issue is one of implementation... It looks > to > me > > > like there are some concerns about usage and the possibility of > unexpected > > > outcomes. MS clearly stated that they understood several of the > > unexpected > > > outcomes and still needed the capability. There are many "unsafe" > things > > > you can do to an HDD, but that has not prevented commands from being > > > implemented. > > > > > > --------------------------- > > > Curtis E. Stevens > > > 29 Dewey > > > Irvine, Ca 92620 > > > > > > Home: (949) 552-4777 > > > E-Mail: [EMAIL PROTECTED] > > > > > > The face of a child can say it all, especially the mouth part of the > > face... > > > ----- Original Message ----- > > > From: "Eschmann, Michael K" <[EMAIL PROTECTED]> > > > To: "T13 List Server" <[EMAIL PROTECTED]> > > > Sent: Monday, June 23, 2003 8:23 AM > > > Subject: RE: [t13] hmmm.. no comments? > > > > > > > > > > This message is from the T13 list server. > > > > > > > > > > > > My (humble?) opinion is that FUA is necessary and is not dangerous > as > > long > > > as a disk drive properly deals with outstanding requests. > > > > > > > > First off a flush is very slow, affecting system benchmark scores > by > as > > > much as 5%. The more interesting fact is that not all drives > properly > > > support flush, where many HDD's will complete the Flush command > without > > > writing any cached data to media just because of the desire to make > ones > > > disk synthetically faster than somebody elses. > > > > > > > > FUA allows the OS to flush critical data without adversely > affecting > > > performance. The drive should be required to test all outstanding > writes > > > (in the queued case) and assure that the writes are ordered to > guarantee > > no > > > data loss. Lets take a look at a specific scenario: > > > > > > > > - Queued write 256 sectors to LBA 10000 > > > > - FUA write 1 sector 10001 > > > > > > > > The 256-sector write must be written to media, or the 1 sector > must > > > over-write the same sector written by the 256 sector write in the > devices > > > cache. The drive must also assure that the media results in the > same > > data. > > > I'm sure we could expand this simple case to something much more > complex, > > > but the basic idea remains: The drive must handle ordering such > that > > there > > > is no data loss. I've asked once before, and I'll ask it again: > someone > > > offer up a more complex scenario where you believe FUA will break > and we > > can > > > then have a real conversation about the (de)merits of FUA. > > > > > > > > MKE. > > > > > > > > > > > > > > > > -----Original Message----- > > > > From: Harlan Andrews [mailto:[EMAIL PROTECTED] > > > > Sent: Friday, June 20, 2003 4:47 PM > > > > To: Andre Hedrick; Steve Livaccari > > > > Cc: Curtis Stevens; T13 List Server; [EMAIL PROTECTED]; Larry > Barras > > > > Subject: Re: [t13] hmmm.. no comments? > > > > > > > > > > > > This message is from the T13 list server. > > > > > > > > > > > > I have not been present at any of the discussions, but > Out-Of-Order > > > > writes are inherently dangerous to ANY file system - not only to > > > > journaling. Now that we have Flush Cache as a mandatory command, > why > > > > don't we simply issue the Flush Cache to force unit access. > > > > > > > > I have not heard any real benefit for such a dangerous operation. > Why > > > > would anyone even consider it ? > > > > > > > > ...Harlan > > > > > > > > on 6/19/03 10:49 PM, [EMAIL PROTECTED] wrote: > > > > > > > > >This message is from the T13 list server. > > > > > > > > > > > > > > > > > > > >Steve, > > > > > > > > > >This totally nukes and destroys write ordered operations. > > > > >Example is the down/commit block on a journalled operation. > > > > > > > > > >Taking an FUA command to platter and blasting past the queue > cache > will > > > > >destroy every bit of the security designed into any journaling > file > > > > >system. > > > > > > > > > >I still do not get why MicroSoft thinks there journaling NTFS of > the > > > > >meta data in OS buffer cache will not take a hit. If I knew the > OS > my > > > > >data was dependent on did such a "FOOLISH" operation I would find > > > another. > > > > > > > > > >If T13 continues to move towards making it possible for the HOST > to > do > > > bad > > > > >things, then the DEVICE is even worse. > > > > > > > > > >We can all pack our bags and go home and switch to T10, because > nobody > > > > >will trust a device coming out of T13 again. > > > > > > > > > >Comments? > > > > > > > > > >Tomato Shield UP!! > > > > > > > > > >Andre Hedrick > > > > >LAD Storage Consulting Group > > > > > > > > > >On Wed, 18 Jun 2003, Steve Livaccari wrote: > > > > > > > > > >> This message is from the T13 list server. > > > > >> > > > > >> > > > > >> > > > > >> All modern HDD's have a buffer for write cache that is used to > stack > > up > > > > >> write data from both queued and unqueued write commands. A > write > > > command > > > > >> followed by a flush cache command will likely not move the data > from > > > the > > > > >> last write command to the media until the rest of the data is > the > > write > > > > >> cache is written. If a write FUA command is used the data from > the > > > write > > > > >> FUA command will be given priority over the other data in the > write > > > cache > > > > >> and be written first. > > > > >> > > > > >> > > > > >> > > > > >> Regards, > > > > >> Steve Livaccari > > > > >> > > > > >> Hard Drive Engineering > > > > >> IBM Global Procurement > > > > >> Internet: [EMAIL PROTECTED] > > > > >> Phone (919) 543.7393 > > > > >> > > > > >> > > > > >> > > > > > > > > > > > > > >> "Curtis Stevens" > > > > > > > > > > > > > >> <[EMAIL PROTECTED] To: "T13 > List > > > Server" > > > > ><[EMAIL PROTECTED]> > > > > >> oo.com> cc: > > > > > > > > > > > > > >> Sent by: Subject: Re: > [t13] > > > hmmm.. > > > > no > > > > >comments? > > > > >> [EMAIL PROTECTED] > > > > > > > > > > > > > >> rg > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> 06/17/2003 11:09 > > > > > > > > > > > > > >> PM > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > > > > > > > > > > >> > > > > >> > > > > >> > > > > >> > > > > >> This message is from the T13 list server. > > > > >> > > > > >> > > > > >> Gary > > > > >> > > > > >> As I recall, there were some inacuracies in the proposals > as > made > > > to > > > > >> the > > > > >> committee. There were many revisions. The only new FUA > commands > > that > > > make > > > > >> sense are the queued ones. All others could be followed by > flush > > > cache. > > > > >> > > > > >> --------------------------- > > > > >> Curtis E. Stevens > > > > >> 29 Dewey > > > > >> Irvine, Ca 92620 > > > > >> > > > > >> Home: (949) 552-4777 > > > > >> E-Mail: [EMAIL PROTECTED] > > > > >> > > > > >> The face of a child can say it all, especially the mouth part > of > the > > > > >> face... > > > > >> ----- Original Message ----- > > > > >> From: "Gary Laatsch" <[EMAIL PROTECTED]> > > > > >> To: "Curtis Stevens" <[EMAIL PROTECTED]>; "T13 List > Server" > > > > >> <[EMAIL PROTECTED]> > > > > >> Sent: Tuesday, June 17, 2003 4:40 PM > > > > >> Subject: Re: [t13] hmmm.. no comments? > > > > >> > > > > >> > > > > >> > Curtis and Hale, > > > > >> > > > > > >> > Also, to expand upon this. I think Hale's point is the > > proposal > > > put > > > > >> > forth by Nita didn't contain the QUEUE FUA or QUEUE FUA EXT > > commands > > > and > > > > >> he > > > > >> > was wondering where they were added or how they were > proposed. My > > > memory > > > > >> was > > > > >> > this was discussed and added at the June 2002 meetings. That > is > > why > > > I > > > > >> was > > > > >> > wondering if anyone else remembered these discussions. I > remember > > > > >> > discussing all of this stuff (even Andre's comments about the > FUA > > > blowig > > > > >> > away the queue) but for some reason it just wasn't captured > very > > well > > > in > > > > >> the > > > > >> > minutes. > > > > >> > > > > > >> > Gary Laatsch > > > > >> > [EMAIL PROTECTED] > > > > >> > > > > > >> > ----- Original Message ----- > > > > >> > From: "Curtis Stevens" <[EMAIL PROTECTED]> > > > > >> > To: "T13 List Server" <[EMAIL PROTECTED]> > > > > >> > Sent: Tuesday, June 17, 2003 3:15 PM > > > > >> > Subject: Re: [t13] hmmm.. no comments? > > > > >> > > > > > >> > > > > > >> > > This message is from the T13 list server. > > > > >> > > > > > > >> > > > > > > >> > > Hale > > > > >> > > > > > > >> > > I was there during the discussions and there was no > secret > > > > >> committee. > > > > >> > > Basically, MS stated that they wanted to force meta data to > the > > > drive > > > > >> > > without blowing the que. This means that although it is > possible > > > to > > > > >> lose > > > > >> > > data, in their application data loss would not occur... > > > > >> > > > > > > >> > > --------------------------- > > > > >> > > Curtis E. Stevens > > > > >> > > 29 Dewey > > > > >> > > Irvine, Ca 92620 > > > > >> > > > > > > >> > > Home: (949) 552-4777 > > > > >> > > E-Mail: [EMAIL PROTECTED] > > > > >> > > > > > > >> > > The face of a child can say it all, especially the mouth > part > of > > > the > > > > >> > face... > > > > >> > > ----- Original Message ----- > > > > >> > > From: "Hale Landis" <[EMAIL PROTECTED]> > > > > >> > > To: "T13 List Server" <[EMAIL PROTECTED]> > > > > >> > > Sent: Tuesday, June 17, 2003 10:57 AM > > > > >> > > Subject: [t13] hmmm.. no comments? > > > > >> > > > > > > >> > > > > > > >> > > > This message is from the T13 list server. > > > > >> > > > > > > > >> > > > > > > > >> > > > I'm curious why there are no comments about the question > of > the > > > > >> > > > origin of the WRITE DMA QUEUED FUA command (where is the > > > proposal?). > > > > >> > > > And why no comments on QUEUED EXT commands with large > sector > > > counts. > > > > >> > > > > > > > >> > > > Is this because all these discussions must take place via > the > > > "secret > > > > >> > > > society"? > > > > >> > > > > > > > >> > > > Hale > > > > >> > > > > > > > >> > > > > > > > >> > > > > > > > >> > > > *** Hale Landis *** www.ata-atapi.com *** > > > > >> > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > >> > > > > >> > > > > >> > > > > >> > > > > > > > > >
