Compellent scv2020 Unallocated space

Question

Hi,I'm having a big space allocation problem with a Compellent Scv2020 storage pair. Initially I had 500GB read-intensive SSD drives on one and 2TB on the other. Given the need for more space, I added 9 7TB disks on the first and 8 on the second. The first is equipped with an additional enclosure so I currently have 25 500GB + 8 7TB + 1 2TB disks on the first storage and 15 2TB + 8 7TB disks on the second storage. The problem is that I have 39TB on the first storage and 54TB on the second storage of unallocated space, 51% on the first and 66% on the second. Unallocated space is mostly on 7TB disks. Storage 1: 38% consumed on 7TB disks, 100% on the single 2TB disk and 99.98% on 500GB disks. Storage 2: 18% consumed on 7TB disks and 73% on 2TB disks; one of the 7TB disks is at 0%.Someone suggested that I start removing the smaller disks because their large number would prevent allocating space on the larger disks, I've tried that but it doesn't seem to work much.I add that the storages are used by some datastores on vsphere 7.I don't know how I could do it. Is anyone able to give me a solution? Kind regards

innen · Answer

Storage1 - 1Storage1 - 2Storage2

DellEMCSupport · Answer

Hello thanks for choosing Dell. May we see your storage profile? Also when did you add the disk?

innen · Answer

Hello, I've added 7TB drives in two steps over the past few months.

innen · Answer

Forgive me, I did not understand which conversation I should read. I should add that I had availability problems a few days ago which I solved by inserting a new disk. So Unallocated space never becomes available, even when free space is used up.

Thanks

DellEMCSupport · Answer

Hello, please check this conversation that explains how SC works with allocated and unallocated space. I don't think that unallocated space is a problem in your configuration. Thanks

DellEMCSupport · Answer

Sorry, this one Dell Compellent Free Space and Allocated Space - Dell Community

innen · Answer

HI,I'm not sure I understood correctly. According to the article, the allocation takes place automatically taking into account various variables: type of raid, number of disks, storage profile, etc. But I experienced unavailability (Alert created on controller '250062' for object [internal ref: 'Read-Intensive SSD'] - [PercentFull]: Disk Folder Read-Intensive SSD has 7 percent or less space remaining available) despite the storage had 30TB of unallocated space, which I fixed by inserting a new disk. My problem is that the storages are unable to use this space as it is occupied by the servers. For example, 15K with raid 6/10 occupy the space at 100%: out of 7.86TB total, 5.18 are used and 2.68 free. While for read-Intensive-SSDs with RAID 5-9 the free space is always very little and when used it runs out. What do you think I could do to be able to use this space?   Regards

DELL-Charles R · Answer

Hello innen,

I think these knowledge articles can help:

Storage Center Alert: Disk Folder < disk folder name > has < x > percent or less space remaining

https://dell.to/3NzhSkn

Understanding RAID with Dell SC Series Storage

https://dell.to/3NbyAoB

Compellent

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