Solstice Disksuite Concat vs. Stripe

Solstice Disksuite Concat vs. Stripe

Post by J.D. Baldw » Fri, 12 Sep 1997 04:00:00





>I've recently set up a large partition across multiple disks using
>Solstice DiskSuite 4.0, and I wanted to check my sanity on this config
>because the GUI interface is a bit confusing..

Yes, it is.  In my opinion, you're a bit better off using `vi md.tab`
since its syntax is unambiguous.

Quote:>I am trying to set it up as a striped partition, to maximize
>performance (with a log device to speed up writes).  I think I have it
>set up correctly, but I am not sure of the language/logic in the admin
>interface and answerbook.

>What I have now is a Concat/Stripe device called d2.  Within that
>device I have Stripe 0 defined with 9 2GB "slices".

And you have a concat of this stripe with other stripes?  Or is it
just a stripe?  There's no such thing as a "Concat/Stripe device,"
really (the unfortunate name of the template in the metatool not-
withstanding), but there are concats of stripes.  (There are, as
far as I know, no stripes of concats, but I suppose it would be
theoretically possible.)

Quote:>My question is: does this mean that it stripes the data across the
>nine disks in that slice?

This question fails to parse.  You can't have multiple disks--much
less nine--in a single slice.  What, exactly, did you mean?  Did you
mean "stripe"?  (Wouldn't life be easier if Sun had just stuck with
the term "partition" like everybody else in the world?)

If you build a stripe across nine disks, then writing a bunch of data
to this stripe will cause 16k to be written to the first disk, the
next 16k to be written to the second, the next 16k to be written to
the third, etc., etc.  16k is only a default; you may change it to
anything you like.

Quote:>Or, should I be defining 9 stripes and putting one partition in each
>of them?

As noted parenthetically above, disks don't have "partitions."  If you
meant "stripe," it doesn't make sense to build a stripe out of a
single slice.  OK, OK, the Answerbook for the metatool uses this
terminology, but I think it's wrong and confusing and in any case
doesn't apply to the statement above.

Quote:>One Stripe:  (Concatenated slices, or striped??)
>http://docs.sun.com:80/cgi-bin/gettransbitmap?trans/safedir/space3/pk...

In this example, the user is building a stripe out of two physical
pieces of disk ("slices"), c6t5d3s0 and c7t0d2s0, then concatenating
this device with another disk slice, c7t0d3s0.  The whole thing is to
be called d8.  I think, in md.tab-speak, this will come out as:

d8      2 2     /dev/dsk/c6t5d3s0 /dev/dsk/c7t0d2s0
          1     /dev/dsk/c7t0d3s0

As part of the example, note that the interleave has been changed from
the default of 16k to 32k, so the above is missing an appropriate '-i'
flag.

Writes to d8 will write 32k to c6t5d3s0, then 32k to c7tod2s0, then
32k to c6t5d3s0, then 32k to c7t0d2s0, and so on back and forth.  When
these devices fill up, writes will begin on c7t0d3s0.

Quote:>Multiple stripes: (Concatenated Stripes or Striped Volume??)
>http://docs.sun.com:80/cgi-bin/gettransbitmap?trans/safedir/space3/pk...

In this example, the user is building *two* stripes--d7 and d6.  Each
of these stripes is built from two physical pieces of disk, or
"slices."  The stripes are then made into submirrors of device d8.  So
every write to device d8 will be made *twice*--once each to d7 and d6
(and those writes will be striped as described above).

In md.tab-speak, this is something very like:

d6      1 2     /dev/dsk/c6t1d2s0 /dev/dsk/c7t0d3s0
d7      1 1     /dev/dsk/c4t0d1s0 /dev/dsk/c5t0d1s0,
d8      -m      /dev/md/dsk/d6

No, I don't understand why d7 doesn't need to be specified on the d8
line, so don't ask.  The md.tab man page doesn't help, either.  That's
just how it's done.

It sounds like what you want is one big, honking 18G stripe made up
of nine 2G slices, no concat, no mirroring, no nothing.  This is
easy enough, and looks like:

d0      1 9     /dev/dsk/c0t0d0s2 /dev/dsk/c0t1d0s2 /dev/dsk/c0t2d0s2 \
                /dev/dsk/c0t0d1s2 /dev/dsk/c0t1d1s2 /dev/dsk/c0t2d1s2 \
                /dev/dsk/c0t0d2s2 /dev/dsk/c0t1d2s2 /dev/dsk/c0t2d2s2

I made up the device names assuming three 2 GB disks on each of three
controllers.  You'll have to figure out the proper setup for your own
configuration, of course.

Also, if you're going to build such a big filesystem with so many
disks, consider building a RAID device instead of a stripe.  It will
cost you a bit of space, and you'll take a performance hit, but a
single disk failure won't hose the whole filesystem, at least.

My further advice is to chuck metatool and use md.tab and metainit to
accomplish this stuff.  This is definitely a case where GUI is a
detriment to understanding and visualization.
--
 From the catapult of J.D. Baldwin  |+| "If anyone disagrees with anything I

 _|70|___:::)=}-  for PGP public    |+| retract it, but also to deny under
 \      /         key information.  |+| oath that I ever said it." --T. Lehrer
***~~~~-----------------------------------------------------------------------

 
 
 

Solstice Disksuite Concat vs. Stripe

Post by J.D. Baldw » Sat, 13 Sep 1997 04:00:00




>I've recently set up a large partition across multiple disks using
>Solstice DiskSuite 4.0, and I wanted to check my sanity on this config
>because the GUI interface is a bit confusing..

Yes, it is.  In my opinion, you're a bit better off using `vi md.tab`
since its syntax is unambiguous.

Quote:>I am trying to set it up as a striped partition, to maximize
>performance (with a log device to speed up writes).  I think I have it
>set up correctly, but I am not sure of the language/logic in the admin
>interface and answerbook.

>What I have now is a Concat/Stripe device called d2.  Within that
>device I have Stripe 0 defined with 9 2GB "slices".

And you have a concat of this stripe with other stripes?  Or is it
just a stripe?  There's no such thing as a "Concat/Stripe device,"
really (the unfortunate name of the template in the metatool not-
withstanding), but there are concats of stripes.  (There are, as
far as I know, no stripes of concats, but I suppose it would be
theoretically possible.)

Quote:>My question is: does this mean that it stripes the data across the
>nine disks in that slice?

This question fails to parse.  You can't have multiple disks--much
less nine--in a single slice.  What, exactly, did you mean?  Did you
mean "stripe"?  (Wouldn't life be easier if Sun had just stuck with
the term "partition" like everybody else in the world?)

If you build a stripe across nine disks, then writing a bunch of data
to this stripe will cause 16k to be written to the first disk, the
next 16k to be written to the second, the next 16k to be written to
the third, etc., etc.  16k is only a default; you may change it to
anything you like.

Quote:>Or, should I be defining 9 stripes and putting one partition in each
>of them?

As noted parenthetically above, disks don't have "partitions."  If you
meant "slice," it doesn't make sense to build a stripe out of a
single slice.  OK, OK, the Answerbook for the metatool uses this
terminology, but I think it's wrong and confusing and in any case
doesn't apply to the statement above.

Quote:>One Stripe:  (Concatenated slices, or striped??)
>http://docs.sun.com:80/cgi-bin/gettransbitmap?trans/safedir/space3/pk...

In this example, the user is building a stripe out of two physical
pieces of disk ("slices"), c6t5d3s0 and c7t0d2s0, then concatenating
this device with another disk slice, c7t0d3s0.  The whole thing is to
be called d8.  I think, in md.tab-speak, this will come out as:

d8      2 2     /dev/dsk/c6t5d3s0 /dev/dsk/c7t0d2s0 \
          1     /dev/dsk/c7t0d3s0

As part of the example, note that the interleave has been changed from
the default of 16k to 32k, so the above is missing an appropriate '-i'
flag.

Writes to d8 will write 32k to c6t5d3s0, then 32k to c7tod2s0, then
32k to c6t5d3s0, then 32k to c7t0d2s0, and so on back and forth.  When
these devices fill up, writes will begin on c7t0d3s0.

Quote:>Multiple stripes: (Concatenated Stripes or Striped Volume??)
>http://docs.sun.com:80/cgi-bin/gettransbitmap?trans/safedir/space3/pk...

In this example, the user is building *two* stripes--d7 and d6.  Each
of these stripes is built from two physical pieces of disk, or
"slices."  The stripes are then made into submirrors of device d8.  So
every write to device d8 will be made *twice*--once each to d7 and d6
(and those writes will be striped as described above).

In md.tab-speak, this is something very like:

d6      1 2     /dev/dsk/c6t1d2s0 /dev/dsk/c7t0d3s0
d7      1 1     /dev/dsk/c4t0d1s0 /dev/dsk/c5t0d1s0
d8      -m      /dev/md/dsk/d6

No, I don't understand why d7 doesn't need to be specified on the d8
line, so don't ask.  The md.tab man page doesn't help, either.  That's
just how it's done.

It sounds like what you want is one big, honking 18G stripe made up
of nine 2G slices, no concat, no mirroring, no nothing.  This is
easy enough, and looks like:

d0      1 9     /dev/dsk/c0t0d0s2 /dev/dsk/c0t1d0s2 /dev/dsk/c0t2d0s2 \
                /dev/dsk/c0t0d1s2 /dev/dsk/c0t1d1s2 /dev/dsk/c0t2d1s2 \
                /dev/dsk/c0t0d2s2 /dev/dsk/c0t1d2s2 /dev/dsk/c0t2d2s2

I made up the device names assuming three 2 GB disks on each of three
controllers.  You'll have to figure out the proper setup for your own
configuration, of course.

Also, if you're going to build such a big filesystem with so many
disks, consider building a RAID device instead of a stripe.  It will
cost you a bit of space, and you'll take a performance hit, but a
single disk failure won't hose the whole filesystem, at least.

My further advice is to chuck metatool and use md.tab and metainit to
accomplish this stuff.  This is definitely a case where GUI is a
detriment to understanding and visualization.
--
 From the catapult of J.D. Baldwin  |+| "If anyone disagrees with anything I

 _|70|___:::)=}-  for PGP public    |+| retract it, but also to deny under
 \      /         key information.  |+| oath that I ever said it." --T. Lehrer
***~~~~-----------------------------------------------------------------------

 
 
 

1. DiskSuite stripe or concat

Hello,

I would like to create a partition which contains two physical slices of
two different disks, so my choice is either to do a stripe or either to
do a concat. The problem is that these two slices are not the same size
and I just read that for stripping the slices have to be the same size
or I will loose space, is that right ? Any opinions about striping or
should I go for concat ?

Regards

2. Netscape 4.7 SMTP error

3. simple [DiskSuite] question , Difference between Stripe and concat ?

4. Need pointer to NCSA patches

5. Activating a DiskSuite Concat/Stripe

6. Problem with KFM /tmp/kfm-cache-o/index.txt

7. vxprint, STRIPE vs CONCAT layout & choosing proper layout

8. console messages

9. Solstice DiskSuite and Striping Parameters

10. RAID, Striping and Solstice Disksuite

11. Solstice DiskSuite and tunefs for striping optimization

12. Veritas Volume Manager vs Solstice DiskSuite

13. On-Line DiskSuite 3.0 to Solstice DiskSuite 4.1 upgrade problem.