Looking for help/direction on reallocating deduplicated volumes. Have a FAS2040 running 7.3.6 and adding an additional DS4243 shelf with SAS drives and want to extend current aggregate by adding a new raid group created with the new disk to the aggregate. On this aggregate I have volumes that are deduplicated and have snapshots. I have read several NetApp documents that seem to conflict on running reallocate on the volumes after adding the new disks to the existing aggregate. I have read you should reallocate but not on a volume that is deduplicated. I have also read that if you use the -p switch this will be OK, reallocate start -f -p /vol/VOLUMENAME.
Will I have problems if I run reallocate on my deduplicated volumes?
Thanks.
Brad
From TR-3929 Reallocate Best Practices:
4.4 Deduplication and Compression Starting in Data ONTAP 8.1 deduplicated data can be reallocated using physical reallocation or read_realloc space_optimized. Although data may be shared by multiple files when deduplicated, reallocate uses an intelligent algorithm to only reallocate the data the first time a shared block is encountered. Prior versions of Data ONTAP do not support reallocation of deduplicated data and will skip any deduplicated data encountered.
Compressed data will not be reallocated by reallocate or read reallocate, and it is not recommended to run reallocate on compressed volumes.
On Thu, Jan 17, 2013 at 1:04 PM, Brad Smith bsmith@iup.edu wrote:
Looking for help/direction on reallocating deduplicated volumes. Have a FAS2040 running 7.3.6 and adding an additional DS4243 shelf with SAS drives and want to extend current aggregate by adding a new raid group created with the new disk to the aggregate. On this aggregate I have volumes that are deduplicated and have snapshots. I have read several NetApp documents that seem to conflict on running reallocate on the volumes after adding the new disks to the existing aggregate. I have read you should reallocate but not on a volume that is deduplicated. I have also read that if you use the -p switch this will be OK, reallocate start -f -p /vol/VOLUMENAME.
Will I have problems if I run reallocate on my deduplicated volumes?
Thanks.
Brad ______________________________**_________________ Toasters mailing list Toasters@teaparty.net http://www.teaparty.net/**mailman/listinfo/toastershttp://www.teaparty.net/mailman/listinfo/toasters
Hi Brad,
We faced a similar situation a while back, wanting to add just a couple of extra disks to an existing RAID group on a FAS2050 running 7.3.6.
After emails to this list, several conversations with NetApp support, etc, the answer we received was that you simply can't reallocate deduplicated data in v7.x - there's no way to do it short of manually moving data out of and back I to the aggregate.
Rather unfortunate - in our case we simply had to abandon the plan to add these extra disks to our RG as we would've ended up with a major hotspot.
--
Matt
On 18/01/2013, at 6:04 AM, Brad Smith bsmith@iup.edu wrote:
Looking for help/direction on reallocating deduplicated volumes. Have a FAS2040 running 7.3.6 and adding an additional DS4243 shelf with SAS drives and want to extend current aggregate by adding a new raid group created with the new disk to the aggregate. On this aggregate I have volumes that are deduplicated and have snapshots. I have read several NetApp documents that seem to conflict on running reallocate on the volumes after adding the new disks to the existing aggregate. I have read you should reallocate but not on a volume that is deduplicated. I have also read that if you use the -p switch this will be OK, reallocate start -f -p /vol/VOLUMENAME.
Will I have problems if I run reallocate on my deduplicated volumes?
Thanks.
Brad _______________________________________________ Toasters mailing list Toasters@teaparty.net http://www.teaparty.net/mailman/listinfo/toasters
It's not as bad as you think.
You can't reallocate deduped blocks in a volume. Not 'the whole volume'.
If you have a 50% deduped volume, then you can still reorder half the blocks.
Which may not be so bad
Sent from my iPhone
On Jan 18, 2013, at 3:50 AM, "Matt Kilham (Stratton Finance)" matt.kilham@strattonfinance.com.au wrote:
Hi Brad,
We faced a similar situation a while back, wanting to add just a couple of extra disks to an existing RAID group on a FAS2050 running 7.3.6.
After emails to this list, several conversations with NetApp support, etc, the answer we received was that you simply can't reallocate deduplicated data in v7.x - there's no way to do it short of manually moving data out of and back I to the aggregate.
Rather unfortunate - in our case we simply had to abandon the plan to add these extra disks to our RG as we would've ended up with a major hotspot.
--
Matt
On 18/01/2013, at 6:04 AM, Brad Smith bsmith@iup.edu wrote:
Looking for help/direction on reallocating deduplicated volumes. Have a FAS2040 running 7.3.6 and adding an additional DS4243 shelf with SAS drives and want to extend current aggregate by adding a new raid group created with the new disk to the aggregate. On this aggregate I have volumes that are deduplicated and have snapshots. I have read several NetApp documents that seem to conflict on running reallocate on the volumes after adding the new disks to the existing aggregate. I have read you should reallocate but not on a volume that is deduplicated. I have also read that if you use the -p switch this will be OK, reallocate start -f -p /vol/VOLUMENAME.
Will I have problems if I run reallocate on my deduplicated volumes?
Thanks.
Brad _______________________________________________ Toasters mailing list Toasters@teaparty.net http://www.teaparty.net/mailman/listinfo/toasters
Toasters mailing list Toasters@teaparty.net http://www.teaparty.net/mailman/listinfo/toasters
Back in Oct 2011 we identified several volumes recommended for reallocation (by reallocate measure), and opened a case to learn the official risks. They ended up citing TR doc recommending no reallocate for deduped volumes
Now I read 8.1 changes this recommendation?
https://communities.netapp.com/message/85020
I am running some more reallocate measures to see if it could help our current latency spike case where we are seeing outlier busy disks.
thanks
On Jan 17, 2013, at 9:35 PM, Jeff Mohler speedtoys.racing@gmail.com wrote:
It's not as bad as you think.
You can't reallocate deduped blocks in a volume. Not 'the whole volume'.
If you have a 50% deduped volume, then you can still reorder half the blocks.
Which may not be so bad
Sent from my iPhone
On Jan 18, 2013, at 3:50 AM, "Matt Kilham (Stratton Finance)" matt.kilham@strattonfinance.com.au wrote:
Hi Brad,
We faced a similar situation a while back, wanting to add just a couple of extra disks to an existing RAID group on a FAS2050 running 7.3.6.
After emails to this list, several conversations with NetApp support, etc, the answer we received was that you simply can't reallocate deduplicated data in v7.x - there's no way to do it short of manually moving data out of and back I to the aggregate.
Rather unfortunate - in our case we simply had to abandon the plan to add these extra disks to our RG as we would've ended up with a major hotspot.
--
Matt
On 18/01/2013, at 6:04 AM, Brad Smith bsmith@iup.edu wrote:
Looking for help/direction on reallocating deduplicated volumes. Have a FAS2040 running 7.3.6 and adding an additional DS4243 shelf with SAS drives and want to extend current aggregate by adding a new raid group created with the new disk to the aggregate. On this aggregate I have volumes that are deduplicated and have snapshots. I have read several NetApp documents that seem to conflict on running reallocate on the volumes after adding the new disks to the existing aggregate. I have read you should reallocate but not on a volume that is deduplicated. I have also read that if you use the -p switch this will be OK, reallocate start -f -p /vol/VOLUMENAME.
Will I have problems if I run reallocate on my deduplicated volumes?
Thanks.
Brad _______________________________________________ Toasters mailing list Toasters@teaparty.net http://www.teaparty.net/mailman/listinfo/toasters
Toasters mailing list Toasters@teaparty.net http://www.teaparty.net/mailman/listinfo/toasters
Toasters mailing list Toasters@teaparty.net http://www.teaparty.net/mailman/listinfo/toasters
It comes from reallocate not being fully effective previous to 8.1, but not because it doesn't work.
I never used measure to know when or why to run. I look at cp-read to write io ratios in statit. Wafl free space health is the issue not data locality IMHO.
Sent from my iPhone
On Jan 18, 2013, at 7:16 AM, Fletcher Cocquyt fcocquyt@stanford.edu wrote:
Back in Oct 2011 we identified several volumes recommended for reallocation (by reallocate measure), and opened a case to learn the official risks. They ended up citing TR doc recommending no reallocate for deduped volumes
Now I read 8.1 changes this recommendation?
https://communities.netapp.com/message/85020
I am running some more reallocate measures to see if it could help our current latency spike case where we are seeing outlier busy disks.
thanks
On Jan 17, 2013, at 9:35 PM, Jeff Mohler speedtoys.racing@gmail.com wrote:
It's not as bad as you think.
You can't reallocate deduped blocks in a volume. Not 'the whole volume'.
If you have a 50% deduped volume, then you can still reorder half the blocks.
Which may not be so bad
Sent from my iPhone
On Jan 18, 2013, at 3:50 AM, "Matt Kilham (Stratton Finance)" matt.kilham@strattonfinance.com.au wrote:
Hi Brad,
We faced a similar situation a while back, wanting to add just a couple of extra disks to an existing RAID group on a FAS2050 running 7.3.6.
After emails to this list, several conversations with NetApp support, etc, the answer we received was that you simply can't reallocate deduplicated data in v7.x - there's no way to do it short of manually moving data out of and back I to the aggregate.
Rather unfortunate - in our case we simply had to abandon the plan to add these extra disks to our RG as we would've ended up with a major hotspot.
--
Matt
On 18/01/2013, at 6:04 AM, Brad Smith bsmith@iup.edu wrote:
Looking for help/direction on reallocating deduplicated volumes. Have a FAS2040 running 7.3.6 and adding an additional DS4243 shelf with SAS drives and want to extend current aggregate by adding a new raid group created with the new disk to the aggregate. On this aggregate I have volumes that are deduplicated and have snapshots. I have read several NetApp documents that seem to conflict on running reallocate on the volumes after adding the new disks to the existing aggregate. I have read you should reallocate but not on a volume that is deduplicated. I have also read that if you use the -p switch this will be OK, reallocate start -f -p /vol/VOLUMENAME.
Will I have problems if I run reallocate on my deduplicated volumes?
Thanks.
Brad _______________________________________________ Toasters mailing list Toasters@teaparty.net http://www.teaparty.net/mailman/listinfo/toasters
Toasters mailing list Toasters@teaparty.net http://www.teaparty.net/mailman/listinfo/toasters
Toasters mailing list Toasters@teaparty.net http://www.teaparty.net/mailman/listinfo/toasters
I've found running reallocation on de-duped volumes (yes, I've done it, I'm a rebel etc etc) results in a better reallocate measure but a much worst hotspot within the volume. Which makes complete sense. As I had very few de-duped volumes with very low de-duplication rates, I didn't notice any performance impact as a result. It was certainly better than if I'd added the handful of disks and not run reallocate. I've only run it the once on those volumes though, and I can't promise my experience would scale to an aggregate full of de-duped volumes with high de-dupe rates.
Peta
On 18 January 2013 16:16, Fletcher Cocquyt fcocquyt@stanford.edu wrote:
Back in Oct 2011 we identified several volumes recommended for reallocation (by reallocate measure), and opened a case to learn the official risks. They ended up citing TR doc recommending no reallocate for deduped volumes
Now I read 8.1 changes this recommendation?
https://communities.netapp.com/message/85020
I am running some more reallocate measures to see if it could help our current latency spike case where we are seeing outlier busy disks.
thanks
On Jan 17, 2013, at 9:35 PM, Jeff Mohler speedtoys.racing@gmail.com wrote:
It's not as bad as you think.
You can't reallocate deduped blocks in a volume. Not 'the whole volume'.
If you have a 50% deduped volume, then you can still reorder half the blocks.
Which may not be so bad
Sent from my iPhone
On Jan 18, 2013, at 3:50 AM, "Matt Kilham (Stratton Finance)" < matt.kilham@strattonfinance.com.au> wrote:
Hi Brad,
We faced a similar situation a while back, wanting to add just a couple of extra disks to an existing RAID group on a FAS2050 running 7.3.6.
After emails to this list, several conversations with NetApp support, etc, the answer we received was that you simply can't reallocate deduplicated data in v7.x - there's no way to do it short of manually moving data out of and back I to the aggregate.
Rather unfortunate - in our case we simply had to abandon the plan to add these extra disks to our RG as we would've ended up with a major hotspot.
--
Matt
On 18/01/2013, at 6:04 AM, Brad Smith bsmith@iup.edu wrote:
Looking for help/direction on reallocating deduplicated volumes. Have a FAS2040 running 7.3.6 and adding an additional DS4243 shelf with SAS drives and want to extend current aggregate by adding a new raid group created with the new disk to the aggregate. On this aggregate I have volumes that are deduplicated and have snapshots. I have read several NetApp documents that seem to conflict on running reallocate on the volumes after adding the new disks to the existing aggregate. I have read you should reallocate but not on a volume that is deduplicated. I have also read that if you use the -p switch this will be OK, reallocate start -f -p /vol/VOLUMENAME.
Will I have problems if I run reallocate on my deduplicated volumes?
Thanks.
Brad _______________________________________________ Toasters mailing list Toasters@teaparty.net http://www.teaparty.net/mailman/listinfo/toasters
Toasters mailing list Toasters@teaparty.net http://www.teaparty.net/mailman/listinfo/toasters
Toasters mailing list Toasters@teaparty.net http://www.teaparty.net/mailman/listinfo/toasters
Toasters mailing list Toasters@teaparty.net http://www.teaparty.net/mailman/listinfo/toasters
-
Brad Smith -
Brian Beaulieu -
Fletcher Cocquyt -
Jeff Mohler -
Matt Kilham (Stratton Finance) -
Peta Thames