With Unity a hot spare is set aside for every 30 disks; they remain unbound drives.  The process of rebuilding a drive from a hot spare is automatic and the system will throttle rebuilds according to the amount of IO.  I hope that helps?

Hi ThomDaleyPPI

Thank you your reply.

First 4 disks of Unity is Vault Disks that contains OS so it has less capacity compared to normal disk packs of four.

(for example, if you have 600GB vault disks, the usable capacity is down to 500 GB.)

When one of vault disks has got failure, the rebuild happens to a spare disk. My question is that if this data being rebuild to a spare will be copied back to a vault disk automatically then a vault disk is arraived?

I hope you know what I mean.

Hi King@NW,

Copy back it not automatic on Unity due to the permanent sparing feature.

More info here (from the doc "Introduction to the Unity Platform - A-Detailed-Review"):

"Multicore RAID – Multicore RAID handles the RAID-based protection on Pools. With Multicore RAID, any unassigned disks are marked as potential spares for use in the case of a drive fault. In the event a drive becomes faulted, a potential spare is selected and becomes a permanent part of the RAID Group. Another feature provided by Multicore RAID is the ability to move a disk within the physical locations of a system. For example, a disk may be moved from one enclosure to another to better balance activity between enclosures and buses. Both assigned and unassigned disks may be relocated within a 5-minute window. Note that moving an assigned disk will temporary result in a degraded RAID Group. Lastly, RAID6 groups that suffer double drive failures will employ a parallel rebuild in order to restore full redundancy as quickly as possible. Spares will be selected and begin the rebuild process immediately following a drive fault."

If this answers your question, please mark the thread as answered.

Andre

Hi,

a copy back is not strictly nessary - it is permanent sparing like on VNX2

if you have a current situation that requires copy back then please open a service request.

Hi

Thank you Reply!

I have more one question.

Please tell me copy back comaand.

Vault Drive(DPE Disk0~3) is faulted.

I think the copyback is necessary after vault disk replaced.

It is not user executable command (and for vault, i think it will be automatic).

Its not a user command – thats why you need to work with customer service

We are working to add customer commands and GUI options for this. For the meantime, get in touch with support (create an SR) and we will assist.

King@NW,

So to summarize this thread,

When a vault drive containing customer data fails, the customer data portion of the drive is rebuilt to a spare disk.

This spare disk will be a permanent part of the pool now.

Once the failed drive is replaced with a new one, this new drive will be considered a spare.

Customer data is not copied back automatically.

As discussed above, this is as designed (permanent sparing feature).

If a customer needs the data back where is was originally for some reason, an SR needs to be created so that support can copy it back.

An internal request was submitted to have this changed so the customer can copy to a spare drive if needed.

As a final note, if this answers all of your questions, please mark the thread and answered.

Hi Andre-san,

> Once the failed drive is replaced with a new one, this new drive will be considered a spare.

I don't think so.

After replacing the system drive(vault drive) to the new disk, not a spare drive.

Because, it contains the OS area is on the system drive.

VNXe3200 is automatically copy back.

"VNXe3200 MCx Multicore Everything"

https://support.emc.com/docu57827_VNXe3200_MCx_Multicore_Everything.pdf?language=en_US

When a system drive (DPE Drives 0-3) fails, Multicore RAID:

• Looks for a suitable replacement in the storage system among unused drives

• If a match is found, the new temporary drive is used to rebuild the user space from the failed system drive

• The failed system drive must be physically replaced in the system.

o Upon doing so, the new drive rebuilds the VNXe system space and then automatically copies the user space back from the temporary drive

o When this process is completed, the temporary drive is marked as unused and freed for use