disk 2 failure on pro

Well, you definitely need more space.

If you are still in warranty (5 years for business models) you should choose something from the HCL - otherwise you will lose support.

Note you would need at least 2 of the larger drives to get any more space in a RAID volume.

What firmware are you running?

RAIDiator 4.2.9 is the firmware . if i replaced drive 2 would the data re form across the new drives.

warranty would be a nice option but i had this given to me . nice gift . would i remove disc two the one that is dead .then wait for it to resync . then buy anotherToshiba 3TB 7200RPM SATA 6GB/s 64MB Cache and replace all drives in the end with these

You need at least 4.2.16 for 3TB disk support.

Are you running 4.2.9 or 4.2.19? 4.2.9 is too old for 3TB support.

First you'd need to upgrade your firmware, since 4.2.9 doesn't support 4K drives. 4.2.24 is the current version, so you are seriously behind.

After the upgrade, you'd replace the bad disk with the NAS running, It should resync.

I have no recommendation either way on the Toshiba. Generally I'd suggest a WDC WD30EFRX or a Seagate ST3000VN000 - both are designed for NAS, and have good warranties. I am running several of the WD30EFRX in my Pro-6, and have had good success. There are a couple of posts that suggest that newly purchased WDC WD30EFRX might have an issue with load-cycle-count - so you might want to go with the Seagate.

On the warranty, if you were given the pro new, then you probably could register it and take advantage of the warranty. Note that there were "pro pioneer" models that only had 3 year warranties, only the pro business models have 5 year.

it wont let me update the firmware

if i install a 3tb drive will i get the full 3tbs ish

You need 2 of the largest size drives to get the full space. There is an 8 TiB growth limit to the volume - though if you have a 4-slot model it is pretty hard to hit it. If you do, you'd need a factory reset. (That might be a good idea in any case, though it requires a full backup, since the data and config are wiped).

And you do need to sort out the firmware upgrade problem first, as 4.2.9 is too old to support the larger drives.

i have the six bay model ..and this time the firmware has upgraded..worked from out side front view.. oddly the drive which was showing a yellow dot has now gone ..but there are still errors in log files

times in the past 30 days. This often indicates an impending failure. Please be prepared to replace this disk to maintain data redundancy.
Wed Nov 27 07:57:00 WET 2013 Detected increasing uncorrectable errors[837] on disk 1 [ST31000340NS, 9QJ4C745]. This often indicates an impending failure. Please be prepared to replace this disk to maintain data redundancy.
Wed Nov 27 07:57:00 WET 2013 Detected increasing pending sector count[837] on disk 1 [ST31000340NS, 9QJ4C745]. This often indicates an impending failure. Please be prepared to replace this disk to maintain data redundancy.
Wed Nov 27 07:54:54 WET 2013 RAID sync finished on volume C. The array is still in degraded mode, however. This can be caused by a disk sync failure or failed disks in a multi-parity disk array.
Wed Nov 27 07:26:12 WET 2013 System is up.
Wed Nov 27 07:26:03 WET 2013 Volume C is approaching capacity: 96% used 76G available
Wed Nov 27 07:26:02 WET 2013 Your ReadyNAS device has been updated with a new firmware image. (RAIDiator-x86 4.2.24)
Wed Nov 27 07:22:14 WET 2013 Rebooting device...
Wed Nov 27 07:22:14 WET 2013 Please close this browser session and use RAIDar to reconnect to the device. System rebooting...
Tue Nov 26 18:35:01 WET 2013 System is up.
Tue Nov 26 18:34:47 WET 2013
Tue Nov 26 18:34:44 WET 2013 Volume scan found and corrected errors.
Tue Nov 26 17:34:01 WET 2013 ATA error count has increased in the last day. Disk 1: Previous count: 113 Current count: 116 Growing SMART errors indicate a disk that may fail soon. If the errors continue to increase, you should be prepared to replace the disk.
Tue Nov 26 08:40:17 WET 2013 Powering off device
Tue Nov 26 08:40:17 WET 2013 Please close this browser session and use RAIDar to reconnect to the device after it is powered back on. System powering off...
Mon Nov 25 19:39:33 WET 2013 Error encountered uploading update image.
Mon Nov 25 19:38:32 WET 2013 Blinking disk lcd 3.
Mon Nov 25 19:38:25 WET 2013 Blinking disk lcd 1.
Mon Nov 25 19:38:02 WET 2013 Blinking disk lcd 1.
Mon Nov 25 19:25:07 WET 2013 ATA error count has increased in the last day. Disk 1: Previous count: 94 Current count: 113 Growing SMART errors indicate a disk that may fail soon. If the errors continue to increase, you should be prepared to replace the disk.
Mon Nov 25 19:25:05 WET 2013 System is up.
Mon Nov 25 19:24:54 WET 2013 Volume C is approaching capacity: 96% used 76G available
Sun Nov 24 14:12:36 WET 2013 Newly added disk has failed SMART test on channel: 2 (/dev/sdb)
Sun Nov 24 13:55:13 WET 2013 Newly added disk has failed SMART test on channel: 1 (/dev/sda)
Sun Nov 24 13:55:06 WET 2013 System is up.
Sun Nov 24 13:54:11 WET 2013 Volume scan found and corrected errors.
Sun Nov 24 12:54:24 WET 2013 Reallocated sector count has increased in the last day. Disk 2: Previous count: 4 Current count: 402 ATA error count has increased in the last day. Disk 2: Previous count: 0 Current count: 6 Growing SMART errors indicate a disk that may fail soon. If the errors continue to increase, you should be prepared to replace the disk.
Sat Nov 23 19:42:21 WET 2013 If the failed disk is used in a RAID level 1, 5, or X-RAID volume, please note that volume is now unprotected, and an additional disk failure may render that volume dead. If this disk is a part of a RAID 6 volume, your volume is still protected if this is your first failure. A 2nd disk failure will make your volume unprotected. It is recommended that you replace the failed disk as soon as possible to maintain optimal protection of your volume.
Sat Nov 23 19:42:21 WET 2013 Disk failure detected.
Tue Nov 19 21:14:12 WET 2013 Volume C is approaching capacity: 97% used 73G available
Mon Nov 4 07:56:41 WET 2013 Volume C is approaching capacity: 99% used 35G available
Sun Nov 3 18:38:33 WET 2013 System is up.
Sun Nov 3 18:37:24 WET 2013 Volume scan found and corrected errors.
Sun Nov 3 11:09:20 WET 2013 Volume C is approaching capacity: 99% used 36G available
Sun Nov 3 04:00:45 WET 2013 Reallocated sector count has increased in the last day. Disk 3: Previous count: 6 Current count: 18 Growing SMART errors indicate a disk that may fail soon. If the errors continue to increase, you should be prepared to replace the disk.
Fri Nov 1 19:00:17 WET 2013 Reallocated sector count has increased in the last day. Disk 1: Previous count: 35 Current count: 38 Growing SMART errors indicate a disk that may fail soon. If the errors continue to increase, you should be prepared to replace the disk.
Wed Oct 30 16:00:17 WET 2013 ATA error count has increased in the last day. Disk 1: Previous count: 93 Current count: 94 Growing SMART errors indicate a disk that may fail soon. If the errors continue to increase, you should be prepared to replace the disk.
Wed Oct 30 06:51:42 WET 2013 Volume C is approaching capacity: 96% used 76G available
Mon Oct 28 10:40:21 WET 2013 System is up.
Mon Oct 28 10:40:06 WET 2013
Mon Oct 28 10:39:24 WET 2013 Volume scan found and corrected errors.
Sun Oct 27 21:36:37 WET 2013 Fan will be recalibrated over the next few minutes.
Sun Oct 27 19:49:18 WET 2013 Error encountered uploading update image.
Sat Oct 12 04:00:45 WEST 2013 ATA error count has increased in the last day. Disk 1: Previous count: 90 Current count: 93 Growing SMART errors indicate a disk that may fail soon. If the errors continue to increase, you should be prepared to replace the disk.
Tue Sep 24 06:34:11 WEST 2013 Volume C is approaching capacity: 99% used 34G available
Mon Sep 23 14:48:41 WEST 2013 System is up.
Mon Sep 23 14:47:44 WEST 2013 Volume scan found and corrected errors.
Sun Sep 22 04:00:17 WEST 2013 ATA error count has increased in the last day. Disk 1: Previous count: 1 Current count: 90 Growing SMART errors indicate a disk that may fail soon. If the errors continue to increase, you should be prepared to replace the disk.
Tue Sep 17 20:00:17 WEST 2013 Reallocated sector count has increased in the last day. Disk 1: Previous count: 34 Current count: 35 Growing SMART errors indicate a disk that may fail soon. If the errors continue to increase, you should be prepared to replace the disk.
Mon Sep 16 06:25:30 WEST 2013 Volume C is approaching capacity: 99% used 35G available
Mon Sep 16 04:00:17 WEST 2013 Reallocated sector count has increased in the last day. Disk 1: Previous count: 25 Current count: 34 Growing SMART errors indicate a disk that may fail soon. If the errors continue to increase, you should be prepared to replace the disk.