40 votes
Accepted
Low-end hardware RAID vs Software RAID
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 ...
- 52.6k
32 votes
Accepted
When adding a new disk to RAID 1, why does it sync unused space?
RAID works below the filesystem level - it doesn't know or care what parts of the disk are "used" or not, it just sees a bunch of blocks and their mirrored counterpart for RAID1. So it has ...
- 18.1k
27 votes
Accepted
Can I build a RAID 5+1 system?
With hardware RAIDs - no, you can't: nesting RAID levels is only supported in very specific cases (ie: RAID50 or 60). If using Linux MD, which is extremely flexible, you can do it easily. Let see how ...
- 52.6k
15 votes
Accepted
How to add hot spare to software RAID1?
If you really want to use 4 disks for a RAID1 array, I suggest you to go with a 4-way RAID1 array. In this manner, should a disk fail, you continue to have triple-protection (3-way array) without ...
- 52.6k
11 votes
Low-end hardware RAID vs Software RAID
Go ZFS. Seriously. It's so much better compared to hardware RAID, and reason is simple: It uses variable size strips so parity RAID modes (Z1 & Z2, RAID5 & RAID6) equivalents are performing @ ...
- 15.6k
11 votes
Accepted
Faulty RAID1 disk now shows as foreign
DO NOT import the foreign configuration. A drive shown as "Foreign" is one that the RAID controller thinks is part of a RAID array, but does not recognize as being part of an existing array on that ...
- 254k
9 votes
Is it possible to recover data from an Intel PERC H710 Adapter RAID Controller disks into another server with SAS controller
LSI/Avago/Broadcom MegaRAID SAS devices happily recognize RAIDs from each other. PERC H710 is such a rebranded controller with LSI chip. Once in my experience we transferred a pair of devices from ...
- 15.9k
8 votes
Accepted
While RAID1 is resyncing after create, can i write files to it immediately?
You can use your RAID array immediately, but writes may be slower while the resync is in progress. The resync will pause while your disk writes occur, and then resume when you are not writing to the ...
- 254k
8 votes
Can I build a RAID 5+1 system?
I would use the 3 disks above in a RAID 5 configuration, and then use them together with the fourth in a RAID 1 configuration. There's an increased operating risk for 'exotic' nested RAID levels, and ...
- 13.9k
8 votes
RAID configuration on new server
VMware doesn't support any sort of a software RAID concept, so you're out of luck here. What you can do however: I. Software RAID (1) Keep your UEFI-controlled & mirrored NVMe drives as a boot ...
- 2,156
7 votes
Accepted
2 x RAID1 vs. RAID10 with four disks
RAID 10 is just stripes over mirrors. That means for every mirror pair only one drive may fail. You also lose 50% of the storage. I don't know how your NAS handles two RAID 1 arrays but it might be a ...
- 4,889
7 votes
HP Smart Array P410: Convert RAID10 to RAID1 OR remove disks from RAID10
I don't participate here as much as I used to, but I see a problem with what you've done. HP Smart Array controllers can accommodate SAS and SATA disks. However, you cannot have an array comprised of ...
- 202k
7 votes
Can ZFS mirror a single disk pool automatically?
Yes, adding a second drive to mirror an existing vdev is pretty easy. Lets say you created your pool like this. I use GPT partition labels like zfs-d1 to make the names nice/reliable. zpool create ...
- 134k
6 votes
Accepted
One drive failed in my RAID 1 array, am I safe to replace it without losing data?
Check whether your server supports hot plug - this is the easiest method: pull out the failed HDD, plug in the new one. Without hot plug, you need to shut down the server, replace the failed disk (...
- 13.9k
6 votes
Raid 1 backup or backup of backup
RAID - no matter what level - is not a backup. It is hardware redundancy and is meant to mitigate any loss of either data OR run time/uptime due to sudden catastrophic hardware failure. RAID will ...
- 1,548
6 votes
Accepted
If two members of a RAID 1 volume have inconsistent bits, how do most RAID controller handle this?
RAID controllers never read from both mirrored drives to compare the data. So the answers is - you’ll get inconsistent read you must detect and handle at the file system level. Modern file systems ...
- 2,240
5 votes
Linux- Convert 2 disk raid1 to raid0
mdadm /dev/md0 --grow --level=0 mdadm: level of /dev/md0 changed to raid0 mdadm /dev/md0 --grow --raid-devices=2 --add /dev/sdb1 mdadm: level of /dev/md0 changed to raid4 //here pause for reshare ...
- 51
5 votes
Accepted
Windows Server 2012 Raid 1
Consider and implement 3-2-1 backup rule. RAID is not backup. Backup the data using Veeam Endpoint or make a clone image using Clonezilla. You could make RAID rebuild if you had RAID configured first. ...
- 3,918
5 votes
Amazon AWS Ephemeral disks and RAID1
Hmm, I'm not sure I would want to mix two so different volumes in a single RAID1. If you do that half of your requests will be served from the slower EBS and half from the faster instance storage and ...
- 26.3k
5 votes
Accepted
Add btrfs devices to raid1 array, increasing total size
2TB of space with 4x redundancy or A quote from official wiki explains it in details: "… btrfs combines all the devices into a storage pool first, and then duplicates the chunks as file data is ...
- 9,740
5 votes
Accepted
What a benefit of RAID 1,5,10 vs every night simple diff backup
RAID is not for backups-it's for availability. If you lose a disk in a RAID setup, your systems can still run. Without RAID, you would have to buy and prepare new disks, and restore your backup before ...
- 3,333
5 votes
SAS Drive Upgrade
Do backup of the whole RAID1 volume. Replace drives and create a new RAID1 Restore backup to "new" RAID1 volume
- 9,210
5 votes
Possible to start a RAID1 setup with a single drive?
Yes, you can! Follow the step-by-step guide below. "Add a Mirror to an Existing ZFS Drive" https://blog.fosketts.net/2017/12/11/add-mirror-existing-zfs-drive/
- 15.6k
4 votes
Accepted
Does RAID 1 have a stripe size?
Sort of. The chunk, stripe, or stride size is the logical data size for a single IO when it is scattered over multiple physical disks [wikipedia: data striping]. This is also the optimal minimum read/...
- 5,203
4 votes
Accepted
RAID 1 Reliability: 4 drives vs 2 Drives + 2 Spare Drives
If by "having 4 drives in RAID" you mean having 4-way RAID1 (ie: 4 duplicate copies of each write), well, this is surely more durable/resilient then a 2-way RAID1 + 2 spares: with 4-way RAID1 all 4 ...
- 52.6k
4 votes
Recommended approach for booting from Linux software RAID for redundancy
I ended up going with a GPT partition table, but sticking with the old Bios boot. This was in-part due to some of the complexities surrounding using RAID for an EFI boot partition - https://unix....
- 182
4 votes
Added 4Tb HDD to Iomega IX2-200 but cannot extend the volume
You did everything except the last two steps: Resizing the logical volume. You have a 1.82TB free showing in your vgdisplay, so you've done everything up to this point correctly. Now you just need to ...
- 254k
4 votes
Accepted
Data layout on RAID-1 Array
There's actually a standard for RAID on-disk data and metadata, and it's called DDF (Disk Data Format). At this point most storage controllers are using it, though you should double check before you ...
- 254k
4 votes
On Ubuntu, how do you recover data from a single disk of a raid array from another device
Let's supose /deb/sdb2 is the old raid 1 member you want to recover. First option: try to reassemble the RAID 1 with the old disk: You need to assemble the degraded RAID array in the new machine, ...
- 518
4 votes
Accepted
mdadm: power failure during raid1 rebuild
Both your drives appear marked as "spare". Stop the array then try reassembling it with the scan option: mdadm --stop /dev/md0 mdadm --assemble --scan If that doesn't work, try mdadm -...
- 7,194
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