There is a "Raid Group" concept even on a DMX .. but -as you noted- applies only to RAID devices .. The "RG" concept in a DMX is quite different from the RG you already know in Clariion
In a DMX you can have 2 different types of RAID .. RAID-S (a proprietary version) and RAID-5 .. With RAID-S you have 3 different symdev that belong to the same Raid Group .. with RAID-5 every symdev have its own raid group .. A Raid Group in DMX term refers to slices of a bigger physical drives while in a CX refers to a group of physical drives bounded with a certrain protection ..
I'm not real clear on what your question is - but I did see your earlier post about the similarities between Clariion raidgroups and Symmetrix diskgroups.
I'm presuming you're attempting to isolate the data from the backend/disk perspective. The reason I'm asking this is that not only can you physically separate your disks but Solutions Enabler allows us the flexibility of creating a creating diskgroups for manipulating luns logically as well.
Since I have the added complexity in my environment of RAID-5 7+1 striping (hey, it's ugly but I inherited it, I didn't build it!). I really wanted to physically separate the disks into diskgroups. And because of all of the databases we have inhouse - it really helps to have the Solutions Enabler diskgroup logical separation as well.
So - you can do both. I hope this helps.... Check out the symdg and symld commands.
Can we say Raidgroup in clariion is same as Diskgroup in symmetrix?.
No, you can't. Well, you could say it, but you'd be wrong.
I'm not sure what you mean and what problem you're trying to solve (if any). You should be aware that a Clariion and a Symm are very different in how they define storage for hosts to use.
Why would you want a disk to not be a part of a disk group?
Naren23 I'm not a big Clariion fan, so I don't know them very much .. Could you please explain me what you MUST define when you create a STG in a Clariion ?? Is it correct to say that an STG is made of the following 2 items ??
*LOL* I guess that depends on how you define "big". Personally I prefer the medium sized CLARiiONs
But seriously, we have more capacity on CLARiiONs in our enterprise than on Symms (the DMX3s are still fairly new to us and the old 8830 was purely mainframe storage). The CLARiiONs are great if they are used properly... and it helps to understand them too.
Stefano, when you refer to "STG" are you talking about Storage Groups? If so they are very simple... An SG is a logical group which contains references to hosts and storage (LUNs). If a host reference is in the same SG as a LUN then the host can see that LUN. If they aren't in the same SG the host can't see that LUN. Basically simplified masking (in Symm terms). There seem to be advantages and disadvantages to both ways of doing it. The CLARiiON way may SEEM simpler, but isn't quite as powerful in some situations.
If you meant something else by STG then please clarify and we'll try again.
On a CLARiiON it IS possible to have a single disk, but you still need to make it a RAID group that is just one disk... then you can mind a LUN on it. There really isn't a lot of call for doing that, because you bypass the potential advantages of having RAID performance and protection on your LUNs, but if you have a need, you CAN do it.
Hmmm I wrote STG (or SG) .. but I was thinking at RAID GROUP ...
Let me straighten my question .. When I define a Raid Group I pick up at least 1 lun (better to start with 2 luns ) and "tie" them together assigning a certrain level of protection (I.E. Raid-5) when I define (hmm bind) the first LUN. If I add another LUN to the same Raid Group I'm forced to use the same protection (Raid-5 in my example) in the same RG.
Am I missing something ??
Back to the original question .. Since a RaidGroup have a "fixed" protection while a Disk Group inside a Symmetrix doesn't have, I see no similarities between those two objects.
BTW I can have a "single-disk" Disk group even on a DMX
Stefano, From a CLARiiON fan (except for the capitalization in the name of the product) you are correct. The only similarity I see between a clariion RAID Group and a symmetrix Disk Group is that they both use disks in some way
A RAID Group though is defined by assigning one or more physical disks, not luns, to the RG. Once the RG is created then luns can be bound which will span all the disks in the group. The RAID type is defined per RG and applies to all luns created within the RG.
In defense of the clariion line, the Cx3 systems are quite good. I have a Cx3-80 with 450 disks on it and it performs very well. It has been in service for a little over a year now and we have not had any issues with it. EMC has really matured their midrange platform with the Cx3 series and FLARE 24. The main drawback that I have seen with them though is the multitasking of layered apps: running clones during production or backups can bog down the system. All that being said I just purchased our first symmetrix, a DMX-4, and am starting to spend a lot of time reading the entries in the symmetrix forum and am enjoying the conversations so far.
AranH from my point of view DMX isn't better then CX .. thei simply are different. Different architecture, different target, different market, different prices (hmm maybe this isn't really true right now ), different functionalities.
Well, we should talk about the CX3-80s.... Mine is fine - for the Windows and the lower end AIX servers. The folks I usually hear from (you know, the squeaky wheels) really should be on the DMX now anyway.
Stefano, Yes, definitely different. I have never had to think in terms of tracks or cylinders when scoping storage before!
We purchased the DMX for our few production front line apps that are high i/o and large (over 2TB database) that need not only the performance and availability but the ability to clone frequently without impact to production.
The clariions I will continue to invest in and deploy for midrange apps and development/candidate environments, as they are a good platform for those targets.
Julianne, Alright! There are now two people from Portland in here! Yeah, my place turned into instant mud over the last week of rain.
If you want to talk about the DMX-4 purchase decision and Cx3-80s email me and I will give you my contact info. The address is aran underscore hoffmann at corvel dot com.
xe2sdc
4 Operator
•
2.8K Posts
0
October 29th, 2007 07:00
There is a "Raid Group" concept even on a DMX .. but -as you noted- applies only to RAID devices
In a DMX you can have 2 different types of RAID .. RAID-S (a proprietary version) and RAID-5 .. With RAID-S you have 3 different symdev that belong to the same Raid Group .. with RAID-5 every symdev have its own raid group .. A Raid Group in DMX term refers to slices of a bigger physical drives while in a CX refers to a group of physical drives bounded with a certrain protection
julianne
92 Posts
0
September 28th, 2007 11:00
I'm not real clear on what your question is - but I did see your earlier post about the similarities between Clariion raidgroups and Symmetrix diskgroups.
I'm presuming you're attempting to isolate the data from the backend/disk perspective. The reason I'm asking this is that not only can you physically separate your disks but Solutions Enabler allows us the flexibility of creating a creating diskgroups for manipulating luns logically as well.
Since I have the added complexity in my environment of RAID-5 7+1 striping (hey, it's ugly but I inherited it, I didn't build it!). I really wanted to physically separate the disks into diskgroups. And because of all of the databases we have inhouse - it really helps to have the Solutions Enabler diskgroup logical separation as well.
So - you can do both. I hope this helps.... Check out the symdg and symld commands.
-jq
Message was edited by:
Julianne Quinn
Jurjen_Oskam
56 Posts
0
September 28th, 2007 11:00
in symmetrix?.
No, you can't. Well, you could say it, but you'd be wrong.
I'm not sure what you mean and what problem you're trying to solve (if any). You should be aware that a Clariion and a Symm are very different in how they define storage for hosts to use.
Why would you want a disk to not be a part of a disk group?
naren23-3_uew
2 Intern
•
220 Posts
0
September 28th, 2007 11:00
Thanks for your reply. I will check those two commands you mentioned in the mail and get back to you with right question.
Naren
naren23-3_uew
2 Intern
•
220 Posts
0
September 28th, 2007 12:00
Jut doing comparison study between symmetrix and clariion for Raidgroup and Disk group.
Because Raidgroup and Disk group has set phyicsl disks from where Lun can be formed.
So only i think concept is same with one difference which I metioned in teh first mail.
Naren
xe2sdc
4 Operator
•
2.8K Posts
0
September 29th, 2007 01:00
* Disks
* Protection
julianne
92 Posts
0
October 1st, 2007 10:00
So .... who *are* the big Clariion fans?
Allen Ward
4 Operator
•
2.1K Posts
0
October 1st, 2007 11:00
But seriously, we have more capacity on CLARiiONs in our enterprise than on Symms (the DMX3s are still fairly new to us and the old 8830 was purely mainframe storage). The CLARiiONs are great if they are used properly... and it helps to understand them too.
Stefano, when you refer to "STG" are you talking about Storage Groups? If so they are very simple... An SG is a logical group which contains references to hosts and storage (LUNs). If a host reference is in the same SG as a LUN then the host can see that LUN. If they aren't in the same SG the host can't see that LUN. Basically simplified masking (in Symm terms). There seem to be advantages and disadvantages to both ways of doing it. The CLARiiON way may SEEM simpler, but isn't quite as powerful in some situations.
If you meant something else by STG then please clarify and we'll try again.
Allen Ward
4 Operator
•
2.1K Posts
0
October 1st, 2007 11:00
On a CLARiiON it IS possible to have a single disk, but you still need to make it a RAID group that is just one disk... then you can mind a LUN on it. There really isn't a lot of call for doing that, because you bypass the potential advantages of having RAID performance and protection on your LUNs, but if you have a need, you CAN do it.
xe2sdc
4 Operator
•
2.8K Posts
0
October 2nd, 2007 00:00
Let me straighten my question ..
When I define a Raid Group I pick up at least 1 lun (better to start with 2 luns
Am I missing something ??
Back to the original question .. Since a RaidGroup have a "fixed" protection while a Disk Group inside a Symmetrix doesn't have, I see no similarities between those two objects.
BTW I can have a "single-disk" Disk group even on a DMX
AranH1
2.2K Posts
0
October 2nd, 2007 15:00
From a CLARiiON fan (except for the capitalization in the name of the product) you are correct. The only similarity I see between a clariion RAID Group and a symmetrix Disk Group is that they both use disks in some way
A RAID Group though is defined by assigning one or more physical disks, not luns, to the RG. Once the RG is created then luns can be bound which will span all the disks in the group. The RAID type is defined per RG and applies to all luns created within the RG.
In defense of the clariion line, the Cx3 systems are quite good. I have a Cx3-80 with 450 disks on it and it performs very well. It has been in service for a little over a year now and we have not had any issues with it. EMC has really matured their midrange platform with the Cx3 series and FLARE 24. The main drawback that I have seen with them though is the multitasking of layered apps: running clones during production or backups can bog down the system. All that being said I just purchased our first symmetrix, a DMX-4, and am starting to spend a lot of time reading the entries in the symmetrix forum and am enjoying the conversations so far.
xe2sdc
4 Operator
•
2.8K Posts
0
October 2nd, 2007 16:00
In a word: DIFFERENT
-s-
julianne
92 Posts
0
October 2nd, 2007 17:00
Well, we should talk about the CX3-80s....
Mine is fine - for the Windows and the lower end AIX servers. The folks I usually hear from (you know, the squeaky wheels) really should be on the DMX now anyway.
We're looking at a DMX-4 .... We should talk!
-jq
AranH1
2.2K Posts
0
October 3rd, 2007 07:00
Yes, definitely different. I have never had to think in terms of tracks or cylinders when scoping storage before!
We purchased the DMX for our few production front line apps that are high i/o and large (over 2TB database) that need not only the performance and availability but the ability to clone frequently without impact to production.
The clariions I will continue to invest in and deploy for midrange apps and development/candidate environments, as they are a good platform for those targets.
Aran
AranH1
2.2K Posts
0
October 3rd, 2007 07:00
Alright! There are now two people from Portland in here! Yeah, my place turned into instant mud over the last week of rain.
If you want to talk about the DMX-4 purchase decision and Cx3-80s email me and I will give you my contact info. The address is aran underscore hoffmann at corvel dot com.
Aran