Which is better: RAID 1 or JBOD using Disk 2 as a back up destination?

[NMitchell]

I am using My Cloud Mirror 6TB (MCM) as shared storage (photos, music & documents) for 2 iMac on a wired network. It is configured as RAID 1 & the performance has been OK but I recently performed a back up of my Photoshop Elements catalogue (+/- 90GB) & for about 5 days after it could take up to 5 minutes to open one of the shares & data via Finder. The CPU on the MCM was at 99% most of the time. I assume that this was because that Disk i was copying to Disk 2?

My question is: does RAID 1 slow performance & would it be better if I reconfigured the MCM to JBOD with Disk 1 being for data storage & Disk 2 being a destination for an internal back up? Does anyone have experience of this?

Thanks
Nicholas

[DarrenHill]

More likely it will be due to the various services on the MCM indexing and cataloguing the files that you added to it (this especially happens with media files like pictures and video). In RAID1 the writing of the files should happen concurrently to both disks, so there is no copying involved (basically they are written twice in parallel).

The disadvantage of using JBOD and doing an internal backup is that if something happens to the device then there may be some data loss of files that were created/updated between the last backup and the failure event. In RAID1 mode the duplicate writing of the files is automatic and done at the time of creation/updating, so there is no such risk. The only advantage of JBOD could be if you only want to do a partial mirroring, with some files duplicated and other files stored on just one drive (to give more available space).

In your usage case I’d probably stick with RAID1. My MCM is configured in JBOD mode, but that’s just because I use one drive as a backup target (for Smartware) and the other for storage of media which is duplicated on a second USB drive attached to the MCM (done manually - whenever I have new files I copy them separately to both disk2 and the USB drive).

[NMitchell]

Darren

Many thanks for your succinct response. This makes it all very clear & I’ll take your advice & stick with RAID 1. Certainly the CPU usage has now settled down & I don’t normally copy such large amounts of data to the MCM at one time as I did with the PSE back up.

Thanks
Nicholas