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2d
comment Does an unplugged hard drive used for data archival deteriorate?
Disk drives do not periodically read and rewrite sectors on their own.
Dec
24
comment MDADM not showing RAID5?
It is not going to be able to recover anything.
Dec
23
comment MDADM not showing RAID5?
@Chopper3, R10 is not "a bunch of R1s", it is a stripe that also stores duplicates. While in the naive near layout on a 4 disk configuration ( and linux has better layouts that also work on 2 and 3 disk configurations ), only one disk needs to be read to rebuild, it is still the same amount of data that needs to be read so it isn't any safer, as the odds of a failure reading one whole disk are the same as reading half of two disks. I'm also aware that this is not a new claim, but I am saying it seems to be founded on the faulty application of statistics that is not borne out in practice.
Dec
22
comment MDADM not showing RAID5?
@Chopper3, well first, how is radi10 any safer than raid5 assuming that is true? Resyncing raid10 has to write exactly the same amount of data. And second, I don't know where they get those theoretical error rates, but they don't seem to match reality or like you said, two or three passes of badblocks on a 2-3 tb disk would be almost certain to get one or two uncorrectable errors and I've done that a number of times and never seen one, so I think their models are a little overly cautious.
Dec
22
comment MDADM not showing RAID5?
You have 4 drives connected to the system, but only two of them seem to be from your raid array. If all 4 are actually connected ( plus the other two disks ), and don't at least show up in the bios or fdisk -l or lsblk, then either they are completely dead or not connected to a working sata port. You might try connecting one at a time to a known working port and rotate through to see if they work that way. If not, then yea, your data is gone.
Dec
22
comment MDADM not showing RAID5?
I guess you didn't understand when I said it before. You have several different raid arrays, and 3 of them are in fact, raid1. The raid5 personality was not loaded before because it was not needed. Your raid5 is not working because you only have 2 out of the 4 drives connected to this machine. You need to connect the other drives.
Dec
22
revised MDADM not showing RAID5?
improved formatting
Dec
22
comment MDADM not showing RAID5?
Highlight the block and click the quote button. The four spaces need to be on every line in the block. Now, this is very odd that sdb doesn't even have a 4th partition, and sdd's looks like it contains a partition table. What does parted -l show?
Dec
22
suggested approved edit on MDADM not showing RAID5?
Dec
22
revised MDADM not showing RAID5?
improved formatting
Dec
22
comment MDADM not showing RAID5?
@Chopper3, why on earth would disk size have anything to do with the decision to use raid10 vs raid5? And raid6 is for 6+ disk arrays, it would be silly to use it with only 4 disks instead of raid10.
Dec
22
comment MDADM not showing RAID5?
You want the output in a code block. Also I asked for mdadm -E on the 4th partition on all 4 drives, not all four partitions on the first drive.
Dec
22
suggested approved edit on MDADM not showing RAID5?
Dec
21
comment MDADM not showing RAID5?
Yep, it is the 4th partition that is your raid5. What about mdadm -E on the other 3 drives?
Dec
21
comment Impact of Over Provisioning to a half used disk
One needs to understand the conditions these tests were run in and how applicable they are to real life. The tests bombard the drive with writes and see how fast it can take them, and for how long. If you look at the graphs, even with no additional over provisioning, they pretty much all handle at least 30 seconds of continuous writing before slowing down at all. So unless your workload consists mostly of copying many gigabyte files to the drive from another fast ssd, you don't really need any additional sparing, certainly not 25% or more.
Dec
21
comment Impact of Over Provisioning to a half used disk
@mestia, the filesystem does not necessarily have to be full currently, only that every block in it has been written at some time in the past, and then possibly freed subsequently. Then without TRIM, the drive has to assume that all of the blocks are still in use, even if they aren't.
Dec
21
comment mount a root disk in mnt
Because an lvm physical volume is not a filesystem you can mount; you have to mount the logical volume.
Dec
21
answered mount a root disk in mnt
Dec
21
comment mount a root disk in mnt
That won't work when the guest is using lvm
Dec
21
comment MDADM not showing RAID5?
The module is loaded automatically when needed. It looks like the 3 raid1 arrays you have activated are smaller partitions, likely for the OS running on the device. The 4th partition is probably your data, so what does mdadm -E /dev/sda4 show?