[OpenIndiana-discuss] sd.conf trouble and illumos bug #3220

[Reginald Beardsley]

Sadly yahoo mail makes a mess of replies embedded in the text :-(

I'll have to try the 3 TB USB drive again.  I certainly can't see any reason that your wildcarding scheme shouldn't work.  If there is a problem it's probably a bug.

There are so many lies being told about geometry that it's hard to say what you should do.  At one point I wound up with a partition that was not 4k aligned if I started with cylinder #1, so I used #2 which was 4k aligned.  However, the 2k aligned partition seemed to work OK, so I'm not certain.  I wasn't willing to leave it that way to avoid wasting a little space.

I can't think of any reason that 512B drives wouldn't work fine aligned to larger boundaries.   The only consequence I can see is some wasted space which really isn't an issue given we're talking pennies per GB.  I can't imagine a performance issue that could result.

It seems to me that the default alignment rules would give less trouble if the alignment was to the most restrictive requirement.

--------------------------------------------
On Mon, 1/6/14, Bryan N Iotti <ironsides.medvet at runbox.com> wrote:

 Subject: Re: [OpenIndiana-discuss] sd.conf trouble and illumos bug #3220
 To: openindiana-discuss at openindiana.org
 Date: Monday, January 6, 2014, 12:08 PM
 
 Hi Reginald,
 
 Thanks for your reply.
 
 In the end, I just booted from a live DVD and plugged that
 drive in on my laptop using a double asterisk as the sd.conf
 line and an 8k block size. A test pool create read back
 ashift=13, which should be fine.
 
 Then I used format -e and fdisk to create a single Solaris
 slice with start and end blocks that would fall on a
 cylinder number that was divisible by 8 (I did it like for
 4K disks, if I'm wrong I'd like some input on that please).
 
 Then I created the rpool in the first slice and moved the
 disk over to the final system, where I sent and received the
 zfs datasets. Change menu.lst, install grub and I was done.
 Working fine so far (160MB/sec sustained on a scrub, normal
 wsvc_time and asvc_time in iostat).
 
 Would anyone see any problem in doing the sd.conf line
 backwards, I mean masking all drives as "**" with a 4K
 blocksize and adding entries for the other 512-byte drives?
 What would happen if ZFS thought a 512-byte block device
 used a 4K block size? Wasted space, performance issue,
 errors?
 
 Thanks, as always, for any and all input.
 
 
    Bryan
 
 
 On Sun, 5 Jan 2014 16:10:58 -0800 (PST)
 Reginald Beardsley <pulaskite at yahoo.com>
 wrote:
 
 > I can't comment on your particular issue which is why I
 didn't respond earlier.  However,  I had trouble
 getting a 3 TB Toshiba USB drive to work properly.  I
 spent a bunch of time reading the code that parses sd.conf,
 but finally gave up and didn't go further.
 > 
 > On reflection I wonder if the problem is a failure to
 propagate the information about block size to ZFS correctly
 under certain circumstances.  I think it would be nice
 if one could force ashift when creating a pool. 
 Automagic is nice, but there's often no substitute for human
 intelligence.  I spent a couple of days trying to
 persuade OI to create a properly aligned pool before I gave
 up.
 > 
 > 
 >  
 > 
 > _______________________________________________
 > OpenIndiana-discuss mailing list
 > OpenIndiana-discuss at openindiana.org
 > http://openindiana.org/mailman/listinfo/openindiana-discuss
 > 
 
 
 -- 
 Bryan N Iotti
 
 +39 366 3708436
 ironsides.medvet at runbox.com
 
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