#software-raid

[sevennet-blog]

Solution: How to make a Linux software RAID1 detect disc corruption? #computers #solution #answer

Solution: How to make a Linux software RAID1 detect disc corruption? #computers #solution #answer

How to make a Linux software RAID1 detect disc corruption?

This is one of the nightmare days: A virtualized server running on a Linux SW-RAID1 runs a VM that exhibits random segfaults in seemingly random codechunks.

While debugging I find that a file gives different md5sums on each and every run. Digging deeper I find this: The raw disc partitions that make up the RAID1 mirror contain 2…

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[sevennet-blog]

How to: Linux mdadm software RAID 6 - does it support bit corruption recovery? #computers #programming #solution

How to: Linux mdadm software RAID 6 – does it support bit corruption recovery? #computers #programming #solution

Linux mdadm software RAID 6 – does it support bit corruption recovery?

Wikipedia says “RAID 2 is the only standard RAID level, other than some implementations of RAID 6, which can automatically recover accurate data from single-bit corruption in data.”

Does anyone know if the RAID 6 mdadm implementation in Linux is one such implementation that can automatically detect and recover from single-bit…

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[sevennet-blog]

Solution: Poor Linux software RAID 5 performance with NCQ #answer #development #computers

Solution: Poor Linux software RAID 5 performance with NCQ #answer #development #computers

Poor Linux software RAID 5 performance with NCQ

While salvaging a 2-disk failure in my 3-disk RAID 5 setup, I happened to notice reconstruction was faster with NCQ disabled (~90M/sec) than with the NCQ enabled (~50M/sec). Running bonnie++ to benchmark the two configurations also revealed significantly better write performance for Sequential Output Block:

no NCQ – 85M/sec, 2021ms latency

NCQ –…

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[sevennet-blog]

Answer: Is RAID5 more robust than RAID1 #solution #it #development

Answer: Is RAID5 more robust than RAID1 #solution #it #development

Is RAID5 more robust than RAID1

I am about to replace an old hardware RAID5 array with a Linux software RAID1 array. I was talking to a friend and he claimed that RAID5 was more robust than RAID1.

His claim was that with RAID5, on read the parity data was read to make sure that all the drives were returning the correct data. He further claimed that on RAID1 errors occurring on a drive will go…

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[sevennet-blog]

Answer: Can I use dmraid instead of md (mdadm) to make software RAID-1 and RAID-1+0 volumes? #development #computers #dev

Answer: Can I use dmraid instead of md (mdadm) to make software RAID-1 and RAID-1+0 volumes? #development #computers #dev

Can I use dmraid instead of md (mdadm) to make software RAID-1 and RAID-1+0 volumes?

On a related question about SSDs and TRIM (see: Possible to get SSD TRIM (discard) working on ext4 + LVM + software RAID in Linux? ), it turns out that dmraid may now (or shortly) support TRIM on RAID-1.

Typically, we’ve used md (via mdadm) to create our RAID-1 volumes, then used LVM to create volume groups,…

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[sevennet-blog]

Answer: 2 drives, slow software RAID1 (md) #programming #fix #development

Answer: 2 drives, slow software RAID1 (md) #programming #fix #development

2 drives, slow software RAID1 (md)

I’ve got a server from hetzner.de (EQ4) with 2* SAMSUNG HD753LJ drives (750G 32MB cache).

OS is CentOS 5 (x86_64). Drives are combined together into two RAID1 partitions:

/dev/md0 which is 512MB big and has only /boot partitions

/dev/md1 which is over 700GB big and is one big LVM which hosts other partitions

Now, I’ve been running some benchmarks and it seems…

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[sevennet-blog]

How-to: SW SSD Raid 1 over HW RAID 10 #answer #dev #solution

How-to: SW SSD Raid 1 over HW RAID 10 #answer #dev #solution

SW SSD Raid 1 over HW RAID 10

A provider(data center) recommended I go with 1TB SSDs in a software RAID 1 over HW RAID 10 with mechanical drives.

Their quote:

Typically SSDs are most reliable than RAID cards and since you have less parts, there are less points of failure. There won’t be much of a CPU load since RAID1 is extremely simple storage.

How true is that and when running virtual…

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[sevennet-blog]

Fixed: Convert linux software raid from raid5 to raid6 #solution #fix #dev

Fixed: Convert linux software raid from raid5 to raid6 #solution #fix #dev

Convert linux software raid from raid5 to raid6

I currently have a file server with 3 1.5TB disks in a RAID5 array. Since it’s pretty much full, I got three additional disks (also 1.5TB each).

Now I’d like to switch to RAID6 since 6TB space is enough and I’d like to have the increased safety of raid6. While I do have a full backup – i.e. I could simply create a new array and restore the backup –…

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