Don't forget to introduce yourself in Coffee Break area of our forums.
As per primus emc87031 it's hard to tell a single limit ... it depends on system resources (mostly available cache) thus I think it's better if you open a SR and ask our Customer Service an answer tailored on your boxes.
The SymmWin program that runs on the Symmetrix Service Processor does not impose a specific upper limit on the number of Virtual Devices that you can create.
Similarly there are no specific limits imposed by the Enginuity microcode on the number of Virtual Devices it can manage (according to a TimeFinder/Clone Engineer).
However, having said this, you will strike other issues that will restrict the number of VDEV's that you can create.
For example, the more VDEV's created will require additional physical cache memory since they are cache resident devices.
The more cache you install the more DA processors will be required (for the EMC Internal "Power Vault" volumes needed to support this physical memory) therefore the maximum supported cache size (and therefore possible number of VDEV's) differs from say a DMX Model 950 to a DMX Model 4500.
The question that really needs to be asked is on what you plan to do with all these Virtual Devices?
Physical disk storage will still be required for the "Save Pool" or SAV devices that go with the VDEV's.
VDEV's have certain functional limitations (e.g. cannot be RDF volumes). So that would also limit the number you may want to create.....
The practical maximum number is something that your local EMC Implementation Specialist or Solutions Architect can help you determine. I hope this helps...
We have a database on 3400 devices (9207Cyl in RAID 5 3 +1) we want to secure with snapshots. Our goal is to make 2 or 3 snaps in our database (10200 vdev). I read in documentation that the EMC limit the number of VDEV was in 8000 in 5771 and 5772 firmware (for 5773 I don't find). We have DMX3-24 (720 disks 146Go,300Go and 80 GB of cache mirror) in 5771,105 firmware. That is why I asked my question without a clear answer from EMC. Best regards, Rodolphe
As Michael has also confirmed the SymmWin program / Enginuity code will allow the creation of more than 8000 VDEV's.
I had added 50,000 (very small) VDEV's to a test bin file yesterday at 5772 and successfully added 20,000 x 4206 cylinder VDEVs on a test Symmetrix today (at 5773). Again there seems to be NO limit on the number that the code will let me create.
However, there are still practical limits on the number that you would want to create (again I would hope that an EMC IS or SA could provide some guidance on the relative quantity to create / activate at the same time).
Unfortunately my expertise is limited to the SymmWin program and Enginuity code, the 8000 limit may be recommendation for performance reasons (perhaps based on copy session limits or Quality Assurance testing)?. Speaking to some colleagues here in the EMC Support Centre they felt that 10200 VDEVs was an unusually high number....
In any case, as Michael has already requested, if you can please forward more details on the EMC document in question we can get back to you with the best possible answer.
Rodolphe can you please send the document to me ?? I think you can easily guess my email address. I'll take care of forwarding the document to anyone inside EMC interested in looking at the document. In case you need help, you can obtain my email address stripping the space between the 2 parts forming my surname, followed by an underscore and later by my name... At emc dot com
--------------------------------------------------------------------------------------------- Ci-desssous un extrait de notre site WEB de Configuration DMX Virtual Devices
VDEV's are configured as CDEV's in 5771 code. - They no longer take up any physical space, reside in memory only. VDEV's must be new devices, cannot convert existing devices. VDEV's must be mirror protected. VDEV's do not support TimeFinder operations VDEV's cannot be RDF devices VDEV's are Host addressable. - VDEV's are NR to the host when no session is active. VDEV¿s can be associated to RAID-10 volumes. - The VDEV must be of the same size as the Raid-10 volume and is established to the head. VDEV¿s can be used with Meta volumes. - The Meta VDEV must be constructed in the same way as the Meta volume Restore can be made from a VDEV to a standard or (split) BCV. VDEV's are not real copies and the PiT can be lost in certain conditions. - Save device full and certain restore operations. VDEV's must be of the same size and geometry as the standard. VDEV's cannot have an alias address, but can be associated to a standard that does have alias's. VDEV's are "Skinny" devices taking up a fraction of hard disk space, but: - They take the same amount of cache table space as the standard device. - splits count toward maximum hyper rules and maximum DA target rules. - count toward the maximum volume count of 8000.
Can you please tell us also the date you received the message ??
Old codes had a maximum of 8000 symdevs .. and the message states what someone else (a couple of Michael) already told: vdevs count as regular symdevs when it comes to max number of symdevs you can create. This does not mean that you have up to 8000 vdevs but that you have up to 8000 symdevs (again, true for OLD codes).
Ahhh!!. I recognize that text - it is from an EMC Internal website. It was added as a configuration summary when the VDEV's were originally introduced some years ago with Enginuity 5669/5670 (circa 2003).
It has been "cut & pasted" into an external document without appropriate modifications (if received after 2004 ).
Yes, VDEV's count towards the maximum number of Symmetrix logical volumes that you can create:
- Enginuity 5670 is limited to maximum 8,192 logical volumes (or 8000 customer addressable volumes). - Enginuity 5671 is limited to a maximum of 16,394 logical volumes (or 16,000 customer addressable volumes). - Enginuity 5771 at GA was limited to 32,768 logical volumes. - Enginuity 5771.81.90 and above (5772 & 5773 included) SymmWin will now allow us to create a maximum of 65,536 logical volumes.
These 64K volumes (on all DMX-3/4) can be physical data volumes or virtual devices. Mystery solved....
xe2sdc
4 Operator
•
2.8K Posts
0
October 23rd, 2008 22:00
Don't forget to introduce yourself in Coffee Break area of our forums.
As per primus emc87031 it's hard to tell a single limit ... it depends on system resources (mostly available cache) thus I think it's better if you open a SR and ask our Customer Service an answer tailored on your boxes.
mlee2
108 Posts
0
October 26th, 2008 19:00
Good question. The quick answer is "no limit".
The SymmWin program that runs on the Symmetrix Service Processor does not impose a specific upper limit on the number of Virtual Devices that you can create.
Similarly there are no specific limits imposed by the Enginuity microcode on the number of Virtual Devices it can manage (according to a TimeFinder/Clone Engineer).
However, having said this, you will strike other issues that will restrict the number of VDEV's that you can create.
For example, the more VDEV's created will require additional physical cache memory since they are cache resident devices.
The more cache you install the more DA processors will be required (for the EMC Internal "Power Vault" volumes needed to support this physical memory) therefore the maximum supported cache size (and therefore possible number of VDEV's) differs from say a DMX Model 950 to a DMX Model 4500.
The question that really needs to be asked is on what you plan to do with all these Virtual Devices?
Physical disk storage will still be required for the "Save Pool" or SAV devices that go with the VDEV's.
VDEV's have certain functional limitations (e.g. cannot be RDF volumes). So that would also limit the number you may want to create.....
The practical maximum number is something that your local EMC Implementation Specialist or Solutions Architect can help you determine. I hope this helps...
Best Regards,
Michael.
rve72
4 Posts
0
October 27th, 2008 09:00
Thank you for your reply.
We have a database on 3400 devices (9207Cyl in RAID 5 3 +1) we want to secure with snapshots. Our goal is to make 2 or 3 snaps in our database (10200 vdev). I read in documentation that the EMC limit the number of VDEV was in 8000 in 5771 and 5772 firmware (for 5773 I don't find). We have DMX3-24 (720 disks 146Go,300Go and 80 GB of cache mirror) in 5771,105 firmware.
That is why I asked my question without a clear answer from EMC.
Best regards,
Rodolphe
mlee2
108 Posts
0
October 27th, 2008 19:00
Thank you for the extra information.
As Michael has also confirmed the SymmWin program / Enginuity code will allow the creation of more than 8000 VDEV's.
I had added 50,000 (very small) VDEV's
However, there are still practical limits on the number that you would want to create (again I would hope that an EMC IS or SA
Unfortunately my expertise is limited to the SymmWin program and Enginuity code, the 8000 limit may be recommendation for performance reasons (perhaps based on copy session limits or Quality Assurance testing)?. Speaking to some colleagues here in the EMC Support Centre they felt that 10200 VDEVs was an unusually high number....
In any case, as Michael has already requested, if you can please forward more details on the EMC document in question we can get back to you with the best possible answer.
Thanks & Best Regards,
Michael.
xe2sdc
4 Operator
•
2.8K Posts
0
October 30th, 2008 06:00
In case you need help, you can obtain my email address stripping the space between the 2 parts forming my surname, followed by an underscore and later by my name... At emc dot com
rve72
4 Posts
0
October 30th, 2008 06:00
I find a mail from "SUPPORT EMC² FRANCE" :
---------------------------------------------------------------------------------------------
Ci-desssous un extrait de notre site WEB de Configuration DMX
Virtual Devices
VDEV's are configured as CDEV's in 5771 code.
- They no longer take up any physical space, reside in memory only.
VDEV's must be new devices, cannot convert existing devices.
VDEV's must be mirror protected.
VDEV's do not support TimeFinder operations
VDEV's cannot be RDF devices
VDEV's are Host addressable.
- VDEV's are NR to the host when no session is active.
VDEV¿s can be associated to RAID-10 volumes.
- The VDEV must be of the same size as the Raid-10 volume and is established to the head.
VDEV¿s can be used with Meta volumes.
- The Meta VDEV must be constructed in the same way as the Meta volume
Restore can be made from a VDEV to a standard or (split) BCV.
VDEV's are not real copies and the PiT can be lost in certain conditions.
- Save device full and certain restore operations.
VDEV's must be of the same size and geometry as the standard.
VDEV's cannot have an alias address, but can be associated to a standard that does have alias's.
VDEV's are "Skinny" devices taking up a fraction of hard disk space, but:
- They take the same amount of cache table space as the standard device.
- splits count toward maximum hyper rules and maximum DA target rules.
- count toward the maximum volume count of 8000.
------------------------------------------------------------------------------------------------------------
Regards,
Rodolphe
rve72
4 Posts
0
October 30th, 2008 06:00
Thank you for your answer.
The EMC document is "Vdev and SAV Devices In a Nut Shell"
I don't kwown how to attach the document in forum.
Best regards,
Rodolphe
xe2sdc
4 Operator
•
2.8K Posts
0
October 30th, 2008 07:00
Old codes had a maximum of 8000 symdevs .. and the message states what someone else (a couple of Michael) already told: vdevs count as regular symdevs when it comes to max number of symdevs you can create. This does not mean that you have up to 8000 vdevs but that you have up to 8000 symdevs (again, true for OLD codes).
Message was edited by:
Stefano Del Corno
mlee2
108 Posts
0
October 30th, 2008 17:00
Ahhh!!. I recognize that text - it is from an EMC Internal website. It was added as a configuration summary when the VDEV's were originally introduced some years ago with Enginuity 5669/5670 (circa 2003).
It has been "cut & pasted" into an external document without appropriate modifications (if received after 2004
Yes, VDEV's count towards the maximum number of Symmetrix logical volumes that you can create:
- Enginuity 5670 is limited to maximum 8,192 logical volumes (or 8000 customer addressable volumes).
- Enginuity 5671 is limited to a maximum of 16,394 logical volumes (or 16,000 customer addressable volumes).
- Enginuity 5771 at GA was limited to 32,768 logical volumes.
- Enginuity 5771.81.90 and above (5772 & 5773 included) SymmWin will now allow us to create a maximum of 65,536 logical volumes.
These 64K volumes (on all DMX-3/4) can be physical data volumes or virtual devices. Mystery solved....
Best Regards,
Michael.
xe2sdc
4 Operator
•
2.8K Posts
0
October 31st, 2008 04:00
without appropriate modifications (if received after
2004
That's why I asked Rodolphe to tell us when he received the mail
ThX again Michael !!
-s-