Re: Is a raid0 512 byte chunk size possible? Or is it just too small?
From: Roman Mamedov <hidden>
Date: 2013-08-31 07:10:09
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From: Roman Mamedov <hidden>
Date: 2013-08-31 07:10:09
On Sat, 31 Aug 2013 01:05:44 -0400 Veedar Hokstadt [off-list ref] wrote:
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