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1784
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Posted October 12th, 2010 11:00
I am afraid not, not sure if Vmax lun migration can do that. Last resort is PowerPath lun migration enabler.
emc243183
1786
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Posted October 12th, 2010 11:00
according to that article you can't expand striped thin LUNs. You are welcome to verify with support, i am interested myself.
1785
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Posted October 12th, 2010 11:00
Dynamox,
Can you please paste summary of the article over here.Thanks
1785
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Posted October 12th, 2010 11:00
"Is there a way to expand / grow an existing thin device?" ID: emc243183 Usage: 7 Date Created: 06/08/2010 Last Modified: 09/21/2010 STATUS: Approved Audience: Customer Knowledgebase Solution Question: Is there a way to expand / grow an existing thin device online? Environment: EMC SW: Solutions Enabler symcli Environment: EMC SW: Symmetrix Management Console Environment: The EMC Solutions Enabler Array Controls CLI Product Guide states the following in the "Configuring thin metadevices" section: "Only unbound thin devices can be formed into a metadevice." Problem: Unbinding thin devices from the pool will result in data loss. Change: The documentation should read: "Only unmapped thin devices can be formed into a metadevice." The following procedure is evidence that this will work.
Fix: Restrictions: - This is an offline event. Access to the device being expanded is forbidden.
- To preserve the data, concatenation is required. The protect_data option is NOT supported with thin devices; therefore, forming a stripped meta or expanding a stripped thin meta will destroy data.
- The device must be unmapped to form a meta or to add a device to the thin meta.
- The thin device you are adding to the meta head (existing production device) cannot be bound to a thin pool.
- The thin device cannot belong to a TimeFinder or SRDF pair. Sessions must be taken down.
- You cannot mix thin and data devices.
To expand the thin device, perform the following steps:
- Unmount the thin device from the host.
- Unmap the thin device that you wish to grow. If on a V-Max you must remove the devices from the storage group first.
- Make sure the device being added to the existing thin device is unmapped.
- Make sure the device being added to the existing thin device is unbound.
- This step currently cannot be done from SMC. An OPT is in progress. From the command line, form a concatenated meta from the existing thin device and add the thin device you wish to use for concatenation. If already a meta, just add the additional device(s) with the "add dev" option. Refer to the example command file below.
- Put the thin meta head back in the storage group or map the device (pre-V-Max).
- Rescan the host for devices.
- Reconfigure devices under path management control.
- Mount the device.
Notes: Example command file for forming a meta: form meta from dev 0010, config=concatenated;
add dev 0013:0014 to meta 0010;Notes: The step 5 SMC issue only applies to forming a meta from a thin hyper 1785
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Posted October 12th, 2010 18:00
Hi Praveen,
Its not possible to expand striped thin meta device while preserving data. Thats the reason we recommend concat thin meta over striped thin meta.
Thanks,
Saurabh
1785
0
Posted October 12th, 2010 19:00
Unless you don't need to expand, then many of us will recommend striped for performance reasons.
1785
0
Posted October 13th, 2010 07:00
Thanks everyone for sharing the info.I have opened a case with emc currently its under engineering review.
1785
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Posted February 1st, 2012 02:00
Please may i have an update on the viability of expanding a thin striped meta on vmax please?
Is it possible to do so and preserve data - i'm guessing that official docs may have updated since this discussion in late 2010, but i'm not yet certain of this frrom forum posts.
thanks
John
620
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Posted February 1st, 2012 06:00
With 5875 code and most recent Solutions enabler we were able to accomplish this. No data loss, etc. Using BCV's.
Process is outlined in "EMC Symmetrix with Microsoft Windows Server 2003 and 2008 Best Practices Planning" page 28.
A RAID 5 BCV metavolume is used to protect data during the migration.
SCSI3_persist_reserv is set on the meta device to expand.
We added the devices to the meta however, we used protect_data=true bcv_meta_head=deviceID
From the document mentioned above...it is fairly strait forward but here is how EMC explains the process.:
quote:
1. The BCV metadevice specified for data protection will begin a clone copy operation from the source metavolume.
2. During the clone copy operation writes from an application, like Exchange, will be mirrored between the source metavolume and the BCV.
3. When the BCV copy is complete, the BCV is split from the source and all read and write I/O is redirected to the BCV device.
4. While the I/O is redirected, the source metavolume will be expanded with the specified volumes.
5. After the metavolume is expanded, the data from the BCV is copied back and restriped across all members of the newly expanded metavolume.
6. During the copy from the BCV, I/O is redirected back to the expanded metavolume.
7. Once the copy back is complete, the BCV clone relationship is terminated and the expansion completes.
:endquote
Once you expand, the administrator needs to extend the partition...
I recommend doing this during a maintenance window when I/O is low...but it can be done online...We've tested it and it works...and it is in an EMC document which also references 5874 code as well...
To do a Proof of Concept you can also take a non-production host and get the process down before you do it in production. I really like practicing
praveen56
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102 Posts
1786
0
Posted October 12th, 2010 11:00
Dynamox,
Are you sure there is no way to expand a thin lun in vmax?