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22 Posts
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20135
June 10th, 2013 04:00
Maintenance Storage Pool - Array Member F/W Upgrade
Hi Team,
I have a two member iSCSI san (PS-300E's) with a default Pool spanning both arrays (total 8.7TB). I need to upgrade the firmware of each array with no disruption.
There are two volumes. Vol1 (Total size: 4Tb, Used: 2.7Tb) and Vol2 (Total Size: 1.2Tb, USed: 1.1Tb)
- Total Used Space therefore = 3.8Tb
- Total combines Vol space = 5.2Tb
Do I simply create another pool (name it maintenance pool and configure size to bit below size of single Array = 4.2Tb) and then move the volumes into it? - allowing me to reboot other Array.
Will it fail if the combined total volume size (5.2Tb) is larger than the maintenance pool size (4.2Tb), or can you migrate both volumes to the new pool if there is enough free space in the volumes. (3.8Tb 'used' is smaller than 4.2Tb)
Hope this makes sense
TIA
DELL-Joe S
7 Technologist
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729 Posts
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June 10th, 2013 07:00
An array member can only be in one pool at a time. Creating a pool without an array member has no storage allocated until a member is added to the pool. Volumes cannot be assigned to a pool until there is storage space in the pool.
Firmware version 3.3.1 is very old and updating will require you to bring the FW up to a version in steps. In your case you will need to do several FW updates (restarting the array in between) to get to the current versions.
On the support site, you can view the required FW update path to get to the latest version (this is in the firmware update guide).
You will need to something like:
v3.x to v4.0.x
then v4.0 to v4.1,
then v4.1 to v4.3
then v4.3 to v5.0
then v5.0 to v5.2
then v5.2 to v6.x
A restart is required between each update. Do both arrays to the same version first, then move onto the next version.
Judging by the number of updates you need, I would suggest you give support a quick call so they can go over the steps in more detail with you.
-joe
DELL-Joe S
7 Technologist
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729 Posts
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June 10th, 2013 09:00
As indicated, pools are just logical names. In order to have usable storage space in a pool, there needs to be at least one array in the pool. Arrays can only be a member of one pool at a time.
The size of the pool is the aggregated size of the members in that pool, this is known as the capacity of the pool. The free space of the pool will be lower due to volumes and meta-data used by the group to operate.
The only way to shrink a pool size is to remove a member from the pool (delete the member from the group/pool), or move a member to another pool. In either case, the remaining member in that pool MUST have enough free space to hold all the volume stored on the member you are removing. You can see the volume distribution on the volume status page.
As Don indicated, you don’t appear to have the free space so that a single member in the default pool can hold all your volume data, while you move one member to a maintenance pool to do the FW update.
This link to the online can help in your understanding of pools, member freespace and volume distribution: psonlinehelp.equallogic.com/.../groupmanager.htm
-joe
pleyden2013
22 Posts
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June 10th, 2013 06:00
My two Arrays are on v3.3.1
DELL-Joe S
7 Technologist
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729 Posts
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June 10th, 2013 06:00
In order to do a “rolling” update, you would need to move one of the members to the Maintenance pool, not the volumes. Members can only be in one pool at a time, and volumes can only be in pools with array members.
Take a look at the KB (on the support site: eqlsupport.dell.com) titled “ARRAY: Updating a multi-member group without down-time”, to see how this is done.
Also, normal firmware updates can usually be done without service disruption, but you should consult the update release notes, iSCSI initiator considerations and update documents to determine if you can do this.
-joe
DELL-Joe S
7 Technologist
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729 Posts
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June 10th, 2013 06:00
I should also add, that if you do decide on the "rolling" update, this requires that the remaining member in the default pool has enough free space to hold all the volume of the member you are moving to the update or "maintenance" pool. When you move a member to another pool, the volumes on that member will stay in the pool and will not move with the member. This is all discussed in the KB mentioned in my prior post.
-joe
pleyden2013
22 Posts
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June 10th, 2013 06:00
Yes, in my orginal post I asked if the used space is enough to calculate, or does it have to be the total allocated space.
You see, the two volumes are only using a small amount of allocated space so could fit on one array, but the total allocated volume space is larger than a single array.
What do you think?
Thanks
pleyden2013
22 Posts
0
June 10th, 2013 06:00
Thanks Joe,
My question is can I create multiple Pools spanning multiple or single arrays?
One Pool (default) that covers the entire Array and its space
Second pool that covers one array.
Third Pool that covers another array etc.
I have seen this forum quesiton too.
en.community.dell.com/.../20112964.aspx
pleyden2013
22 Posts
0
June 10th, 2013 08:00
Thanks again Joe, my upgrade plan includes the firmware steps you mentioned, so its good to have that validated. However, sorry, I'm still unsure with the pools. Can I create multiple pools, (a maintenance pool for example) that is the same size as one of the arrays, and copy the volumes into it allowing me to reboot one of the arrays in a non-disruptive manner.
If so, is the volume size worked out on allocated space, or used space?
thanks
pleyden2013
22 Posts
0
June 10th, 2013 09:00
Oh. I can't reduce the size of a pool?
DELL-Joe S
7 Technologist
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729 Posts
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June 10th, 2013 10:00
1. Yes
2. Shrining a volume isn't as simple as making it smaller in the GUI. The array is a block device and has no knowledge of the OS stored on the volume, so you MUST FIRST shrink the file system on the Server (Host OS) that is using the volume. This is done on the host, using the operating system tools.
If you don't shrink the OS first, you will destroy your data. Also, some operating systems do not allow shrinking, or can do shrinking while online.
If you can shrink the OS file system then, once the OS shrink is completed, you can shrink the volume in the GUI (leave the volume slightly larger for miscalculations).
3. Provided you freed up enough space, plus an additional 10% (for array functions), yes.
Shrinking a volume has some risks (not sizing properly), so make backups of your data.
-joe
pleyden2013
22 Posts
0
June 10th, 2013 10:00
Thanks. OK so
1. it looks like I can create pools no problem, as I don't have to assign a member straight away. Therefore I can create a Maintenance Pool (with no members)
2. I can shrink volumes through CLI in order to reduce the unused space so that the combined 'in-use' and 'free' space on both volumes is less than the size of a single array
3. This will allow me to then move a member to the maintenence storage pool and perform the f/w upgrades non-disruptively.
What you think?
pleyden2013
22 Posts
0
June 10th, 2013 11:00
Thanks Joe,
The current san is used for an ESXi 5.1 installation, so would shrinking away some of the 'free' space be ok? (I know with windows you have to be careful, though Windows 2008 natively reduces)
pleyden2013
22 Posts
0
June 10th, 2013 11:00
Actually, forget that,I'll need to destroy the datastore and recreate (whilst vmotioning guests off). Looks like I'll need to do this out of hours and shut down all the servers while the SAN is upgraded.