Talk:How to prepare a Hard Disk whilst installed in a Synology NAS
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Will it help me convert my 2 drive raid 1 407 to a 3 drive raid 5 407?
Hi, this is an interesting article.
Will it help me convert my 2 drive raid 1 407 to a 3 drive raid 5 407?
Thanks, Martin.
- Martin, it will help you prepare your new disk before you upgrade your volume from RAID1 to RAID5. However, after preparing your new disk (which is optional) you will need to then follow seperate instructions to upgrade from RAID1 to RAID5. I don't know where these instructions are. I suspect they will be in the Synology manual for the CS-407, but perhaps not?
- RobinGB
shred gives the same endresult, but with progress output
While wiping with dd partitions/hard discs works excellent, the user is presented with no progress information. Usage of
shred -v -n 0 -z /dev/[device]
gives the same endresult, but with progress output. Please note, that shred is part of coreutils.
Risto
- Hi Risto, I installed GNU coreutils and then tried shred (shred -v -n 0 -z /dev/sdb) just to see how it worked, however what I found was it only took 2 hours to complete a disk (500Gb) that takes the dd command 20.5 hours. Consequently I am not convinced shred does every bit of the disk, perhaps it only does parts of the disk with files on it? Can anyone give a definative answer on whether shred does every writeable bit on the disk, and if so why it does it in 1/10th the time of the dd command?
- RobinGB
Hi Robin, shred sure works every sector of the disc. Infidel can use hexedit to take a look of the disc contents with own eyes... 20,5h for 500GB doesn't sound correct anyway, this makes just under 6,7 MB/sec which is way slow. You get greatly faster performance with Synology products and FTP protocol over the network, which means that local access HAS to be faster than that. You probably didn't specify with dd the block size. The default block size is very small, causing big processor and head seek overhead Try:
dd if=/dev/zero of=/dev/[device] bs=1M
and you should get similar performance to shred, just without progress indication.
Cheers, Risto
Hi Risto, thanks for this excellent help. You are right I did not specify a block size with the dd command. I will try dd again with the bs=1M option and update the article. I also reformatted this page and my previous entries as per Trolli's request (see below). Thanks, RobinGB
Wiping swap partition
Before wiping sda2 (swap partition) it might be wise to turn off swap first by issuing:
swapoff -a
- Risto 20:51, 18 April 2008 (UTC)
Hi Risto, thanks again, I have updated the article to include all your improvements incuding shred which I have mentioned under the "pre-installation" section. Thanks, RobinGB 21/4/2008
