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[shredhead1260]

I have just purchased a DNS-345 and currently have a DNS-323 using Alt-F firmware.

I plan to use RAID 5 with 4 identical 2TB disks. In thinking about how I move the data over to the DNS-345, I came up with these questions. I'm hoping to be able to copy the data over inside the unit rather than over the network.

1) can you set up the DNS-345 with RAID 5 made up of three disks, then add a fourth disk afterwards without losing data?  the idea is to copy data from the 4th disk onto the RAID 5 and then make it part of the RAID 5. I know you can't just add it to the RAID 5 right away since it would get wiped out.

2) can the DNS-345 have more than one disk group? e.g. a RAID 5 with three disks AND at the same time a JBOD made up of a 4th drive.

3) can the DNS-345 read an EXT 4 volume on a disk that was previously inside a DNS-323? in my case the DNS-323 runs Alt-F rather than stock firmware but I am not sure that matters.

4) According to the manual, the DNS-345 has RAID 1 to RAID 5 migration which can be done without data loss.  This could be the thing for me to use, but that is assuming #3 is true, that it can read my disks. Does this actually work? Who has used it?

[ivan]

There should be no problem reading Ext4 formatted drives because Ext4 formatted RAID 1 drives can be read in a standard Linux computer.

BUT, as with all migrations it is always wise to have a tested backup - things can go wrong and then that backup becomes invaluable.

I must say that we have never done what you propose because we prefer a clean format to the RAID version required and then a restore from the backup.  That serves two things, 1) we know the disks have been setup correctly (these units use a software RAID), 2) the data is being written to the disk/s in the most efficient way possible.

Another point.  As far as I know there is no way to read directly from one disk to another in the NAS unless it is rebuilding a RAID array.  Yes, you can do it through a computer (you then have two way traffic from NAS to computer and back again).  It would generally be quicker to mount one of the RAID 1 disks in an SATA/USB caddy/adapter and use a Linux computer (or a windows one with an IFS that can read Ext4) to do the copying to the NAS.
 

[shredhead1260]

what is it you have never done?  you mean adding a disk to an existing RAID 5?

Yes, if my ideas didn't work, I do have a portable USB I can do the sneakernet approach with.  Are you saying that would be faster?

[ivan]

I assumed that you were getting two new drives to add to the two you already have and I also assumed that the two from your DNS-323 were setup as RAID 1.

We have never tried to split a RAID array and use one of the disks as a JBOD for the simple reason the new enclosure will not recognise it as a JBOD unless it has been formatted as such.  Remember this is a software RAID setup that requires the disks to be tagged with type of usage, a hardware RAID is a total different animal.

Speed, which ever way you do it will be dependant on how fast the data can be read and then written to the new array.  If you will be reading from the NAS to the computer and back again to the NAS there will be the overhead of the two way traffic and possible link congestion.  USB to computer to NAS could be a little faster.  Exactly how long it will take depends on the amount of data and the size of the files as is normal when transfering any data over a network. 

[shredhead1260]

Unfortunately the DNS-345 could not read my disks from the DNS-323. In addition, the DNS-323 does not want to mount my USB drive. So I'm forced to copy all the data (1TB) over the network to the USB drive connected to my Windows machine. I'll then have to do a clean setup of the RAID 5 on the DNS-345.

[FurryNutz]