I had the same question a while ago. The first thing I thought of was using WMI, but for some weird reason, WMI doesn’t expose the health of a RAID volume through any of the normal Win32_* classes. I eventually stumbled across the script in this article and made a few modifications to suit my … Read more
Patches for mdraid RAID 1 and 10 support for TRIM went up about a year ago. You can test your kernel’s support by mounting the filesystem with the discard option (which enables automatic TRIM). If it is supported, you’ll see a message in syslog or dmesg like the following: EXT4-fs (md1): re-mounted. Opts: discard,data=ordered Otherwise … Read more
cat /proc/mdstat will give you the output you need, relatively easy to parse, because the mapped device is on the same line as its members, e.g.: $ cat /proc/mdstat Personalities : [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] [linear] [multipath] md0 : active raid1 sdf2[1] sde2[0] 81854336 blocks super 1.2 [2/2] [UU] md127 : active raid0 … Read more
Linux software RAID is not going to protect you from bit corruption and silent data corruption is a well known issue with it. In fact, if the kernel is able to read the data from one disk it would never know that it is bad. The RAID only kicks in if there is an I/O … Read more
A 10-20$ “hardware” RAID card is nothing more than a opaque, binary driver blob running a crap software-only RAID implementation. Stay well away from it. A 200$ RAID card offer proper hardware support (ie: a RoC running another opaque, binary blob which is better and does not run on the main host CPU). I suggest … Read more
Actually I think Wikipedia explains it better than the actual docs. Here’s the text from the article. The Linux kernel software RAID driver (called md, for “multiple device”) can be used to build a classic RAID 1+0 array, but also (since version 2.6.9) as a single level with some interesting extensions. The standard “near” layout, … Read more
This is not really an answer as there is not enough context to give the exact cause, but it is a description of how I managed to track this when it happened to me. I noticed my jbd2/md0-8 kept showing up at the top of iotop. I looked in /sys/kernel/debug/tracing/events/jbd2 to see what options there … Read more
Based on your problem description your issue isn’t so much the server as the storage. You want a reliable, robust filesystem like ZFS that’s designed to handle large storage capacity well, and has built-in management capabilities to make that end of the system easier to manage. As was mentioned in the comments, I’d go with … Read more
The GRUB wiki confirms: Also, (as of 1.96+20080724) GRUB can only boot from RAID which uses a Version 0.90 metadata superblock (i.e. one created with the –metadata=0.90 option to mdadm). Curiously, the man page for mdadm says -e , –metadata= Declare the style of superblock (raid metadata) to be used. The default is 0.90 for … Read more
With linux softraid you can make a RAID 10 array with only two disks. Device names used below: md0 is the old array of type/level RAID1. md1 is the new array of type/level RAID10. sda1 and sdb2 are new, empty partitions (without data). sda2 and sdc1 are old partitions (with crucial data). Replace names to … Read more