Re: Is a raid0 512 byte chunk size possible? Or is it just too small?
From: Veedar Hokstadt <hidden>
Date: 2013-09-07 19:57:39
Just to close this out. The making a 4TB image file of the raid0 was not feasible for me so I ended up using a commercial raid recovery app that could handle the 512 byte chunk. Thanks for your help. -V On 8/31/13, Roman Mamedov [off-list ref] wrote:
quoted hunk ↗ jump to hunk
On Sat, 31 Aug 2013 01:05:44 -0400 Veedar Hokstadt [off-list ref] wrote:quoted
I am totally aware of the complications involved but if I can somehow build a raid0 / chunk 512B array with mdadm using the raw Lacie dives then I can take it from there to recover the data.You can write a simple program to read in chunks of 512 bytes from one drive, then from the other, piece this together and write to some third file. Here is something quick that I modified from a tool I already had. Even though it's doing the tight loop in PHP, it seems to do about 100 MB/sec reading from two SATA drives and writing to a file on a RAID6 in my system.--- merge.php ---#!/usr/bin/php <?php $f = array(); array_shift($argv); foreach($argv as $arg) { if(($f[] = @fopen($arg, "rb"))===false) die("Unable to open file $arg.\n"); } while(@$feof_cnt<2) { $feof_cnt=0; foreach($f as $file) { print(fread($file, 512)); if(feof($file))$feof_cnt++; } } ?> --- Usage: ./merge.php /dev/sda /dev/sdb > image.img And you will need somewhere to store this image.img that's has the free space to fit the size of sda+sdb. Also check that you specify the drives in the proper order (only 2 tries, really). -- With respect, Roman