All 9 messages in topic - view as tree
From: Octavio Gomez - view profile
Date: Thurs, Aug 3 2006 1:35 am
Email: "Octavio Gomez"
Hi everyone,
I used to work with servers with a bunch of disks connected to them, so it was relative easy to design dbspaces and tables fragmentation in that scene.
Is there any special consideration for dbspaces, chunks and tables fragmentation design in SAN environments with dozens or hundreds of disks inside of one array?
Thank you for your opinions!
Octavio Gomez
Reply Rate this post: Text for clearing space
From: Neil Truby - view profile
Date: Thurs, Aug 3 2006 8:29 am
Email: "Neil Truby"
"Octavio Gomez"
news:mailman.121.1154561456.20706.informix-list@iiug.org...
>> Hi everyone,
>> I used to work with servers with a bunch of disks connected to them, so
>> it was relative easy to design dbspaces and tables fragmentation in that
>> scene.
.. Is there any special consideration for dbspaces, chunks and tables
fragmentation design in SAN environments with dozens or hundreds of disks
inside of one array?
Don't waste time doing anything more than rudimentary placement planning.
The level of indirection between the LUNs presented to your host and the
physical disks is so high as to make the exercise worthless.
Reply Rate this post: Text for clearing space
From: Floyd Wellershaus - view profile
Date: Thurs, Aug 3 2006 11:49 am
Email: Floyd Wellershaus
When we were carving out our luns, we plaided them.
We made raid 10 across 6 disks, then stripped the logical volumes also.
Then, when we started carving out the luns, we realized that the first lun we made from each volume group, was the outer portion of the disk. The second lun was a little farther in and so on.
We decided that the disk would have faster access to the outer portions, so we put our busiest dbspaces in the first lun, and so on.
========================
-<
Database Administrator
Unix Administrator
email: fwell...@yahoo.com
Home: 703-430-0805
Cell: 703-477-6045
========================
http://www.one.org/
- Hide quoted text -
- Show quoted text -
----- Original Message ----
From: Neil Truby
To: informix-l...@iiug.org
Sent: Thursday, August 3, 2006 2:29:53 AM
Subject: Re: dbspaces design in SAN arrays
"Octavio Gomez"
news:mailman.121.1154561456.20706.informix-list@iiug.org...
>> Hi everyone,
>> I used to work with servers with a bunch of disks connected to them, so
>> it was relative easy to design dbspaces and tables fragmentation in that
>> scene.
.. Is there any special consideration for dbspaces, chunks and tables
fragmentation design in SAN environments with dozens or hundreds of disks
inside of one array?
Don't waste time doing anything more than rudimentary placement planning.
The level of indirection between the LUNs presented to your host and the
physical disks is so high as to make the exercise worthless.
_______________________________________________
Informix-list mailing list
Informix-l...@iiug.org
http://www.iiug.org/mailman/listinfo/informix-list
Reply Rate this post: Text for clearing space
From: Mark D. Stock - view profile
Date: Thurs, Aug 3 2006 11:11 pm
Email: "Mark D. Stock"
Octavio Gomez wrote:
> Hi everyone,
> I used to work with servers with a bunch of disks connected to them, so
> it was relative easy to design dbspaces and tables fragmentation in that
> scene.
> Is there any special consideration for dbspaces, chunks and tables
> fragmentation design in SAN environments with dozens or hundreds of
> disks inside of one array?
If you can, allocate different LUNs to each dbspace. Make sure you choose
an appropriate LUN RAID level, i.e. no RAID5. Each LUN can be configured
differently and moved around, so if you can keep to one dbspace per LUN and
you run into performance or storage issues, you can get that LUN reconfigured.
Use fragmentation as normal, even if you are not 100% sure about the
physical location of your data, it's also about allocating more CPU
resources. If you manage to saturate the SAN storage, then get your SAN
Administrator to reconfigure that LUN. ;-)
If you have enough invested in your SAN, you should also be able to play
with business continuity volume (BCV) snapshots using external backups. Who
doesn't like to see a several hundred Gb level 0 archive complete in a
couple of seconds? :-D
Cheers,
--
Mark.
+----------------------------------------------------------+-----------+
| Mark D. Stock mailto:mdst...@MydasSolutions.com |//////// /|
| |///// / //|
| +-----------------------------------+//// / ///|
| |We value your comments, which have |/// / ////|
| |been recorded and automatically |// / /////|
| |emailed back to us for our records.|/ ////////|
+----------------------+-----------------------------------+-----------+
Reply Rate this post: Text for clearing space
From: Neil Truby - view profile
Date: Fri, Aug 4 2006 12:49 am
Email: "Neil Truby"
"Mark D. Stock"
news:mailman.134.1154639919.20706.informix-list@iiug.org...
> If you can, allocate different LUNs to each dbspace. Make sure you choose
> an appropriate LUN RAID level, i.e. no RAID5. Each LUN can be configured
> differently and moved around, so if you can keep to one dbspace per LUN
> and you run into performance or storage issues, you can get that LUN
> reconfigured.
...
> If you have enough invested in your SAN, you should also be able to play
> with business continuity volume (BCV) snapshots using external backups.
> Who doesn't like to see a several hundred Gb level 0 archive complete in a
> couple of seconds? :-D
If you're talking about BCVs this implies you're using EMC Symmetrix. If
you have a Symmetrix you are *absolutely* wasting your time aligning LUNs
and dbspaces, for the reasons I gave earlier.
Is it only me who thinks this?! I keep reading people with expensive SANs
advocating orthodoxies from the days when you were lucky if you had two
disks (one of which was for the OS and swap anyway), and wonder if I'm
missing something ...
Reply Rate this post: Text for clearing space
From: Mark D. Stock - view profile
Date: Mon, Aug 28 2006 1:19 am
Email: "Mark D. Stock"
- Hide quoted text -
- Show quoted text -
Neil Truby wrote:
> "Mark D. Stock"
> news:mailman.134.1154639919.20706.informix-list@iiug.org...
>>If you can, allocate different LUNs to each dbspace. Make sure you choose
>>an appropriate LUN RAID level, i.e. no RAID5. Each LUN can be configured
>>differently and moved around, so if you can keep to one dbspace per LUN
>>and you run into performance or storage issues, you can get that LUN
>>reconfigured.
> ...
>>If you have enough invested in your SAN, you should also be able to play
>>with business continuity volume (BCV) snapshots using external backups.
>>Who doesn't like to see a several hundred Gb level 0 archive complete in a
>>couple of seconds? :-D
> If you're talking about BCVs this implies you're using EMC Symmetrix. If
> you have a Symmetrix you are *absolutely* wasting your time aligning LUNs
> and dbspaces, for the reasons I gave earlier.
> Is it only me who thinks this?! I keep reading people with expensive SANs
> advocating orthodoxies from the days when you were lucky if you had two
> disks (one of which was for the OS and swap anyway), and wonder if I'm
> missing something ...
Well try it for yourself:
1. Get yourself a multi-processor box, with at least 4 CPUs.
2. Set up IDS with at least 3 CPU VPs.
3. Create a non-fragmented table and populate it with some data.
4. Run some benchmarks on it.
5. Now fragment the table across at least 3 dbspaces, all on the same disk,
logical or physical
6. Run the same benchmarks and compare times.
Cheers,
--
Mark.
+----------------------------------------------------------+-----------+
| Mark D. Stock mailto:mdst...@MydasSolutions.com |//////// /|
| |///// / //|
| +-----------------------------------+//// / ///|
| |We value your comments, which have |/// / ////|
| |been recorded and automatically |// / /////|
| |emailed back to us for our records.|/ ////////|
+----------------------+-----------------------------------+-----------+
Reply Rate this post: Text for clearing space
From: Neil Truby - view profile
Date: Mon, Aug 28 2006 11:33 am
Email: "Neil Truby"
"Mark D. Stock"
news:mailman.363.1156732291.20706.informix-list@iiug.org...
- Hide quoted text -
- Show quoted text -
> Neil Truby wrote:
>> "Mark D. Stock"
>> news:mailman.134.1154639919.20706.informix-list@iiug.org...
>> Is it only me who thinks this?! I keep reading people with expensive
>> SANs advocating orthodoxies from the days when you were lucky if you had
>> two disks (one of which was for the OS and swap anyway), and wonder if
>> I'm missing something ...
> Well try it for yourself:
> 1. Get yourself a multi-processor box, with at least 4 CPUs.
> 2. Set up IDS with at least 3 CPU VPs.
> 3. Create a non-fragmented table and populate it with some data.
> 4. Run some benchmarks on it.
> 5. Now fragment the table across at least 3 dbspaces, all on the same
> disk,
> logical or physical
> 6. Run the same benchmarks and compare times.
I don't understand what benchmarks for Informix fragmentation will tell me
about the allocation and positioning of LUNs on a SAN.
Reply Rate this post: Text for clearing space
From: Mark D. Stock - view profile
Date: Fri, Sep 1 2006 7:18 pm
Email: "Mark D. Stock"
- Hide quoted text -
- Show quoted text -
Neil Truby wrote:
> "Mark D. Stock"
> news:mailman.363.1156732291.20706.informix-list@iiug.org...
>>Neil Truby wrote:
>>>"Mark D. Stock"
>>>news:mailman.134.1154639919.20706.informix-list@iiug.org...
>>>Is it only me who thinks this?! I keep reading people with expensive
>>>SANs advocating orthodoxies from the days when you were lucky if you had
>>>two disks (one of which was for the OS and swap anyway), and wonder if
>>>I'm missing something ...
>>Well try it for yourself:
>>1. Get yourself a multi-processor box, with at least 4 CPUs.
>>2. Set up IDS with at least 3 CPU VPs.
>>3. Create a non-fragmented table and populate it with some data.
>>4. Run some benchmarks on it.
>>5. Now fragment the table across at least 3 dbspaces, all on the same
>>disk,
>>logical or physical
>>6. Run the same benchmarks and compare times.
> I don't understand what benchmarks for Informix fragmentation will tell me
> about the allocation and positioning of LUNs on a SAN.
Nothing, but the question was about dbspaces, chunks & table fragmentation:
> Octavio Gomez wrote:
>
> Is there any special consideration for dbspaces, chunks and tables
> fragmentation design in SAN environments with dozens or hundreds of
> disks inside of one array?
And you implied this was a waste of time:
> Neil Truby wrote:
>
> Don't waste time doing anything more than rudimentary placement planning.
> The level of indirection between the LUNs presented to your host and the
> physical disks is so high as to make the exercise worthless.
Sorry if I misunderstood your recommendations.
Cheers,
--
Mark.
+----------------------------------------------------------+-----------+
| Mark D. Stock mailto:mdst...@MydasSolutions.com |//////// /|
| |///// / //|
| +-----------------------------------+//// / ///|
| |We value your comments, which have |/// / ////|
| |been recorded and automatically |// / /////|
| |emailed back to us for our records.|/ ////////|
+----------------------+-----------------------------------+-----------+
Reply Rate this post: Text for clearing space
From: darko - view profile
Date: Fri, Sep 1 2006 9:36 pm
Email: "darko"
- Hide quoted text -
- Show quoted text -
Mark D. Stock wrote:
> Neil Truby wrote:
> > "Mark D. Stock"
> > news:mailman.134.1154639919.20706.informix-list@iiug.org...
> >>If you can, allocate different LUNs to each dbspace. Make sure you choose
> >>an appropriate LUN RAID level, i.e. no RAID5. Each LUN can be configured
> >>differently and moved around, so if you can keep to one dbspace per LUN
> >>and you run into performance or storage issues, you can get that LUN
> >>reconfigured.
> > ...
> >>If you have enough invested in your SAN, you should also be able to play
> >>with business continuity volume (BCV) snapshots using external backups.
> >>Who doesn't like to see a several hundred Gb level 0 archive complete in a
> >>couple of seconds? :-D
> > If you're talking about BCVs this implies you're using EMC Symmetrix. If
> > you have a Symmetrix you are *absolutely* wasting your time aligning LUNs
> > and dbspaces, for the reasons I gave earlier.
> > Is it only me who thinks this?! I keep reading people with expensive SANs
> > advocating orthodoxies from the days when you were lucky if you had two
> > disks (one of which was for the OS and swap anyway), and wonder if I'm
> > missing something ...
> Well try it for yourself:
> 1. Get yourself a multi-processor box, with at least 4 CPUs.
> 2. Set up IDS with at least 3 CPU VPs.
> 3. Create a non-fragmented table and populate it with some data.
> 4. Run some benchmarks on it.
> 5. Now fragment the table across at least 3 dbspaces, all on the same disk,
> logical or physical
> 6. Run the same benchmarks and compare times.
> Cheers,
> --
> Mark.
Small amendment:
Regarding the number of CPU VPs on a 4 CPU server:
with faster CPUs, it may be very advantageous to have 2 or 3 CPU VPs
per CPU that is to execute IDS. At least, that is my experience with
SPARCs running at >1 GHz (haven't tried slower SPARCs, except very old
ones). For more info, look at some posts to c.d.i related to the number
of CPU VPs for use with fast CPUs. I think Art Kagel provided clear
explanation why is it advantageous.
Darko Krstic
Reply Rate this post: Text for clearing space
End of messages
No comments:
Post a Comment