30
votes
Can I make md (Linux software RAID) more fault tolerant?
When you do a backup, you read a lot of data. Probably the drive returns read errors, and is dropped for that reason. This may only happen for some specific area of the drive, which is not normally ...
- 9,274
23
votes
Can I make md (Linux software RAID) more fault tolerant?
A single read-error will not kick-off the disk from the array, at least on post-2012 kernels.
From md man page:
In later kernels, a read-error will instead cause md to attempt a
recovery by ...
- 50.7k
13
votes
Can I make md (Linux software RAID) more fault tolerant?
I had a similar problem. I first checked the drive's SMART info for read error count, but there weren't any. Yet the OS reported errors and the drive got kicked out of the RAID.
It turned out to be a ...
- 361
6
votes
How do data centers deal with constant disk failure?
Your math is wrong
(1-0.016)^1000 is the probability that you will make it through a whole year without a single drive failure (with a pool of 1000 disks), but you don't just multiply 1 year by that ...
- 1,492
5
votes
Data corruption when disk write caching is enabled
Modern file systems (XFS, ZFS, JFS, ext4, APFS, NTFS, etc) all use journaling so yes, you’re going to lose some data (latest commits and what’s not committed yet and stored in cache, that’s obvious), ...
- 14.1k
2
votes
Currently unreadable sectors on RAID 5 linux drive
The accepted answer is generally good, but since mdadm 3.3 you can replace a drive in the array without removing the faulty one first. If the faulty drive mostly readable this protects you from most ...
- 31
2
votes
To improve SQL performance, why not just put lots of RAM rather than having faster hard disks?
Over the years I’ve done ton of work in the space. Here’s what you really have to consider. The first thing is is how largest you’re working data set. You ideally want your working data set to be cash ...
- 21
2
votes
Benchmarking hard disks on Mac OS X SL
Using file copy in general and dd in particular isn't the great way to measure I/O performance. This is a very good wrap up about WHY it's so.
https://barreto.home.blog/2014/08/18/using-file-copy-to-...
- 14.1k
2
votes
Accepted
Can a faulty cable (or other issue) cause SMART errors with a perfectly good drive?
Current_Pending_Sector and Reallocated_Sector_Ct are counters specifically dedicated to tracking media errors, but they are not the only attributes denoting issues.
WRITE/READ FPDMA QUEUED errors ...
- 50.7k
1
vote
How can a folder size be greater than the actual disk capacity on Ubuntu?
If the copy isn't link aware, it creates additional copies for linked files/directories, increasing the amount of data. In extreme, with a looping link, a link-unaware copy could produce an infinite ...
- 11.7k
1
vote
Accepted
vmstat + on RHEL machine high values of swpd
You have 1 GB of 15 GB of swap space used on a machine with a total of 122 GB RAM. Does this value indicate a problem? No.
As long as you have zero or minimal swap in/out (si/so columns) then the ...
- 10.3k
1
vote
Accepted
Shrink/Reduce disk size on a Linux RAID 1 server
On the system which was built with possible rearrangements in mind, this could be as easy as connect other devices, initialize them, migrate volumes and reinstall the boot loader, and that might be ...
- 12.6k
1
vote
Accepted
RHEL + how to prevent OS disk - sda to change after reboot
Use persistent identifiers in /etc/fstab for mounting, e.g., replace /dev/sdX with UUID or symlink from /dev/disk/by-id.
Optionally, add scsi_mod.scan=sync to GRUB_CMDLINE_LINUX in /etc/default/grub ...
1
vote
Debian 11 fails to update grub configuration
The problem was that though grub was booting properly there were references to the imaged machine's disk on:
/var/lib/dpkg/info/grub-pc.postinst
/var/lib/dpkg/info/grub-pc.preinst
Delete both files ...
- 31
1
vote
Curious? LVM on a brand new drive?
OK, seems i managed to delete that LVM stuff, following https://unix.stackexchange.com/questions/411206/how-to-wipe-md-raid-meta
[root@myPC]# mdadm --stop /dev/md127
mdadm: stopped /dev/md127
[root@...
- 181
1
vote
What is a good choise for heavily used data storage
But now I swaped both cables (power and SATA) from failed disk to this
one and the number of errors rose dramatically. How likely is that
something is that either sATA controller or power (though it ...
- 33.3k
1
vote
Adding a disk to an existing RAID fails with "disk doesn't have enough capacity"
Make Firmware Versions Match
Ideally, they should be a version identified in the controller's compatibility list as certified compatible but the first thing you want to do is update the firmware to ...
- 111
1
vote
Accepted
Prefetched Small File Cache
Quantify what acceptable performance would be. Perhaps downloading all of a small sized project takes no more than one or two seconds. Having performance objectives defined by user experience makes ...
- 33.3k
1
vote
Unit for Total_LBAs_Written in SMART data
241 Total_LBAs_Written is in sector size.
smartctl /dev/sda --all |grep "Sector Size" usually gives 512 bytes.
(with /dev/sda your drive).
241 Total_LBAs_Written 0x0032 099 099 000 ...
1
vote
mdadm assemble ignoring --force? Raid10 minimal difference in 'Actions' between Harddisks
Note that --force is ignored if a RAID4/5/6 volume is dirty and degraded. In that case using --force behaves the same as without --force, no additional warning or error is produced. In my case mdadm --...
- 111
1
vote
How to unlock an SSD disk with hdparm?
Very late answer but I have landed here after a few days banging my head against the wall with an HDD locked with an ATA password that I never set (still no idea what set it in the first place).
The ...
- 111
1
vote
Benchmarking hard disks on Mac OS X SL
I have yet to find an equivalent for hdparm on macOS.
Someone mentioned using dd to get at least a basic idea with a command that is available, which is a little bit helpful. They admitted to not ...
- 111
Only top scored, non community-wiki answers of a minimum length are eligible