Ubuntu Servers :: RAID 5 Software Array With 3TB Drives
Jun 15, 2011
I am trying to use 3 3TB Western Digital drives in a raid 5 software array. The trouble seems to be that the array is created with only 1.5 TB of capacity, rather then the expected 6 TB.
Here are the commands and output:
$ sudo dmraid -f isw -C BackupFull6 --type 5 --disk /dev/sde,/dev/sdf,/dev/sdg --size=5589G
Create a RAID set with ISW metadata format
RAID name: BackupFull6
RAID type: RAID5
RAID size: 5589G (11720982528 blocks)
RAID strip: 64k (128 blocks)
DISKS: /dev/sde, /dev/sdf, /dev/sdg
About to create a RAID set with the above settings. Continue ? [y/n] :y
$ sudo dmraid -s
*** Group superset isw_cdjhcaegij
size : 3131048448
stride : 128
type : raid5_la
status : ok
devs : 3
spares : 0
So I cannot understand why the size of the created array is only 3131048448 or about 1.5 TB. The first command seemed to imply it was going to create an array with 5589GB.
Description: Ubuntu 10.04.2 LTS
I have a NETGEAR ReadyNAS NV+ with four 1TB drives in a RAID-5 array. This is our primary file storage. This has previously been backed up to a hardware RAID-0 array directly attached to our Windows server. The capacity of this backup array is no longer sufficient. So the plan was, take a bunch of 200GB to 320GB drives (And a 750) I had kicking around, chuck them in a couple of old SCSI drive enclosures I have collecting dust, attach them via IDA/SATA-to-USB adaptors to a USB hub, attach that to the server, create a JBOD array spanning the disks, and back up the NAS to that. Performance is not an issue as this is just to be used for backup, with the idea being as near to zero cost as possible (Spend so far = NZ$100�ish).
The first hurdle I struck was Windows not supporting Dynamic Disks on USB drives (Required to create a spanned volume). At first I resisted using another machine (i.e. a machine running Ubuntu) as I didn't want to dedicate a piece of hardware to backing up the NAS. I then decided it would be acceptable to do this via a VM, which is what I've done.So I have 10.04 running under VMWare Server 2.0.2 under Windows Server 2008 R2. The disks are all presented to the VM. I wasn't sure if I was going to end up creating the array under LVM or something else, but I noticed Disk Utility has an option to create an array, so I tried that. When I add two 250GB drives, the array size is 500GB. When I then add a 160GB drive, the array size drops to 480GB. Huh? If I keep adding disks (Regardless of order) the final array size comes out at 1.8 TB, as per the attached screenshot. Now with the following drives, I expected something more like:
I want to make a RAID5 array with 4 2TB hard drives. One of the drives is full of data so I will need to start with a 3 disks and then once I copy the data from the 4th onto the array, I will then add the 4th drive. This will be my first experience with RAID. I've spent a few hours searching for info but most of what I have found is a bit over my head.
I got my system up and running with the Grub installed on my primary hard drive. I have not installed 2 additional drives. I would like to combine the 2 additional drives into a RAID 1 array. I can only find tutorials on how to do this during initial install. I cannot find one that tell me how to do it after the install. Is there a way?
I'm renting a dedicated server with a company that claims that the server has 2 hard drives in a software RAID 1 array, but I need to make sure that the server really has the 2 HDD, and the size of the 2nd drive... how to do that ?? system is Centos 5.3
I'm breaking into the OS drive side with RAID-1 now. I have my server set up with a pair of 80 GB drives, mirrored (RAID-1) and have been testing the fail-over and rebuild process. Works great physically failing out either drive. Great! My next quest is setting up a backup procedure for the OS drives, and I want to know how others are doing this.
Here's what I was thinking, and I'd love some feedback: Fail one of the disks out of the RAID-1, then image it to a file, saved on an external disk, using the dd command (if memory serves, it would be something like "sudo dd if=/dev/sda of=backupfilename.img") Then, re-add the failed disk back into the array. In the event I needed to roll back to one of those snapshots, I would just use the "dd" command to dump the image back on to an appropriate hard disk, boot to it, and rebuild the RAID-1 from that.
Does that sound like a good practice, or is there a better way? A couple notes: I do not have the luxury of a stack of extra disks, so I cannot just do the standard mirror breaks and keep the disks on-hand, and using something like a tape drive is also not an option.
I am learning software raid 1 with centos 5.5. I created the raid with out any problems and removed the first drive to check there was no problems and it booted. I have installed the old drive back in the system as hdc and need to resync the drives (used old drive as partitions correct) I thought I could use raidhotadd but id does not seem to exist anymore. how I resync the drives in the array hda primary and hdc secondary using mdadm
This is message I get when I try and start itmdadm: /dev/md0 assembled from 2 drives - not enough to start the arrayBelow is the information I've collected about any help on how I can get the raid back up and going to I can get the data off of it would be awesome
I have a home samba server with a 3ware Escalade 8506-8. I have 5 x 500 gig hard drives in a RAID 5 array. Recently, my 8506 died and I need to get a new one. However, I saw a 3ware Escalade 9500S-12 on ebay for about $20.00 dollars more than a replacement 8506-8.
My question is, if I put my drives on the 9500S, will it recognize my existing RAID array? Or will it want to build a new RAID array and format all of my data?Hope I have asked this question clearly, little short on sleep this week.
I'm about to install Ubuntu on two 250-gigabyte hard drives in a RAID 1 array, but I'm confused about how to partition my hard drives. How much space should I give to each partition? How many partitions should I create and where should I mount them? (I should mention that Ubuntu will be the only OS on this array.)
I have an Areca hardware RAID array that I'm trying to format & partition on a fresh Ubuntu 10.04 LTS installation. The OS drive is not on the RAID card, it's entirely separate. The RAID is a 6TB volume so I realize I have to use parted to format it, not fdisk (which I've always relied on).
My problem is that I can't figure out how to get parted to like my settings. It seems like everything I try gives me the warning "Warning: The resulting partition is not properly aligned for best performance." Here's what I'm doing:
Code: (parted) p Model: Areca ARC-1280-VOL#00 (scsi)[code].....
What start/end settings should I use to get a properly aligned partition? How do I know?I have tried a mix and match of 0, 0s, 1, 1s, -0, -0s, -1, -1s, 100% for my start/end with no success.
I just restarted my server (Ubuntu 9.04 server, running on ESXi 4.0) and while copying files onto the server using samba I got strange problems and the connection was lost. When I rebooted the total system, so ESXi as well as Ubuntu Server I did find problems on my RAID disk.
The directory, where the new files were added I have a lot of files, but a lot of them do not have any info except their name:
so my servers 7 hds in raid 5 all was working well until one of them died. The HD that died sort of works it can read like half a file also freezes on the benchmark test in disk utility. Unfortunate when i take it out on boot it says. The drive for /media_kbt is not ready or present press s to skip or m for manual recovery. I hit s and then go to disk utility. But i can't start or add disks to the array.
I'm currently experiencing some serious issues with WRITE performance on a RAID-1 array. I'm running Ubuntu 10.04 64 bit server with the latest updates. To evaluate the performance ran the following test: [URL]... (great article btw!) Using dd to measure, write performance is only at 8.7 MB/s. Read is great though at 74.5 MB/s. The tests were ran straight after rebooting and I have not (YET!) done any kernel tuning or customization, running the default server package of the Ubuntu kernel. Here's the motherboard in the server: [URL]... with a beta bios to support drives over 300GB.
As you can see from the bo column there is definitely something stalling. As per top output, the %wa (waiting for i/o) is always around %75 however as per above, writes are stalling. CPU is basically idle all the time. Hard drives are quite new and smartctl (smartmontools) does not detect any faults.
I have an ubuntu 10.04 machine that I use primarily as a file server. I have a RAID5 array built with mdadm from 3 component disks that worked properly until a recent upgrade (I'm not sure exactly what broke it though). The array is /dev/md0 and is set to mount at /var/media on bootup. *Now*, when the system cold boots it hangs partway through the bootup sequence and throws the following error:
The disk drive for /var/media is not ready yet Press S to skip ... Once I "S"kip this manually, I can see that LOWER in the boot sequence mdadm gets called and assembles the drive, and once fully booted into the system I can then simply do a "mount -a" and the array mounts properly. SO... my gut feeling is that some portion of one of the upgrades changed the order in which things are called, and now the "mdadm assemble" is not triggered until AFTER the system tries to mount the drives. My problem is that I don't know the stuff that controls the boot sequence well enough to dig in the right place.
As a workaround I can remove that entry from /etc/fstab, but then (of course) the system won't auto-mount the array. It's better than the boot process completely hanging because as least THIS I can fix remotely, but I'd really like to know
1) why this broke in an upgrade and is it a known problem? 2) how to get it back to where it auto-assembles and then auto-mounts the array on bootup.
Ubuntu Server 11.04 i386. I've used linux on and off for years but only in small doses, so I'm really just at newbie level. I was running an Openfiler NAS, but decided to give Ubuntu+Webmin a try. And up 'til now I've been happy with progress. I have set up a RAID-6 array using 5 x 1TB SATA drives. I've ensured that the array is in a "clean" state, and now I want to do some failure testing. The problem occurs when I remove one of the drives in the array. I shutdown, remove a drive, then boot up. The array wont start at all, and comes up with this error during boot:
the disk drive for /mnt/raidvol1 is not ready yet or not present Continue to wait; or Press S to skip mounting or M for manual recovery
If I wait, nothing happens. Obviously the RAID array should start in degraded mode, but it fails to mount at all. When I press "M" to go into manual recovery and type "mount -a" I get the response:
mount: special device /dev/RAIDVG1/RAIDLV1 does not exist
I have set BOOT_DEGRADED=true in /etc/initramfs-tools/conf.d/mdadm without success. If I reconnect the disconnected drive, the array works fine, and is in a clean state.
I'm trying to delete directories (long story, Mac temp files there, Windows not cooperating) on a sever connected to a HP 20 Modular Smart Array set up as RAID5. System currently running Windows. I've booted from a 9.10 LiveCD but can't see the external drives. Is it correct that I need to install mdadm to "see" those drives from LiveCD? From a different machine (linux) I can mount the drive using samba like so:
I've got a couple of new hard disks that I have partitioned (3 partitions per disk) and set up in a mirrored software raid array using mdadm. They've synced, I've put file systems on them (1 x ext4, 2 x luks + ext4) and I can mount them. I've checked the partitions using fdisk. I've checked the filesystems using fsck. So far so good. Next step is that I'd like mdadm to automatically assemble them on boot. (Not bothered about mounting and crypttabing yet.)
I've used sudo /usr/share/mdadm/mkconf to generate a new mdadm.conf with the appropriate UUIDs for the new partitions. I've checked that this matches the output of sudo mdadm --detail --scan
Short story: I have a problem with one of my services (mediatomb) - it requires an md RAID array to be mounted in order to start, because it uses files from it. $remote_fs is added by default to the "Required-Start" line of the init script, so I thought that this should be enough. However, the mediatomb service fails to start on boot, but starts just fine when I execute "service mediatomb start" later. The array is entered in /etc/fstab and is automatically mounted on boot.
This is my file server (Ubuntu Server 10.10), which has a raid array created with mdadm (mounted on /z), and the root filesystem is located on an USB thumb drive. I've installed mediatomb, but I wanted to put its database files on the raid array instead of the root fs, so I've symlinked /var/lib/mediatomb (the default path) to /z/mediatomb on the array. This is because the mediatomb DB is supposed to be updated fairly often, so I didn't want it to stay on the flash drive.
Problem is, the mediatomb service can't start on boot - in /var/log/mediatomb.log, it says "2011-03-07 19:22:47 ERROR: /var/lib/mediatomb : 20 x No such file or directory". As I said, it works fine when manually started later...
This is the fstab entry for the raid array code...
I've recently started having an issue with an mdadm RAID 6 array that been operational for about 2500 hours.
Intermittently during write operations the array stalls, dropping to almost 0 write speed for 10-30 seconds. When this occur one or both of the 2 drives attached to a 2 port Silicon Image si3132 SATA-II controller "locks up" with its activity light locked on. This just started occurring within the last week and didn't seem to coincide with any update that i noticed. The array has just recently passed 12.5% full. The size of the write does not seem to make any difference and it seems completely random. Some times copying a 5 GB dataset results in no slow down other times a torrent downloading to the array at 50kb/sec does cause a slow down and vise versa.
The array consists of 8 WD 1.5TB drives, 6 attached to the ICH9R south bridge, and 2 attached to a si3132 based PCI express card. The array is formatted as a single ext4 partition.
Checking SMART data for all drives shows no errors. Testing read speed with hdparm reports what i would expect (100mb/sec for each drive, ~425mb/sec for the array).
The only thing i did notice is that udma6 is enabled for all the ICH9R drives while only udma5 is enabled for the si3132 drives. Write cache is enabled for all the disks. Attempting to set the si3132 drive to udma6 results in an IO error from hdparm.
The si3132 drive is using the sata_sil24 driver. Nothing of interest appears in the kern or syslog. During this time top shows very high wait time.
The s13132 controller appears to have the original firmware from 2006 loaded, there are some firmware updates available on the Silicon Image website for this controller that now appear to offer separate firmwares for RAID operation (some sort of hybrid controller/software thing the controller supports) and a separate firmware for standard IDE use.
Has anyone had similar issues with this controller? Is a firmware update a reasonable course of action? If so which firmware is best supported by the linux driver?
I know i'm not using its raid features but i've dealt with controllers that needed to be in raid mode for ahci to be active and for linux to work well with them. I'm bit ify at the idea of just trying it and finding out as it could knock 2 disks of my array out of action.
Using a fresh copy of server 10.04 im trying to simulate a failed raid array on a pair of 2tb disks. Here is the procedure i have been following so far:
- Remove the dead disk partitions from each of the raid 1 arrays (substitute the correct md devices and partitions) - mdadm /dev/md0 -r /dev/sdb2 - mdadm /dev/md1 -r /dev/sdb3
I get an error here that sfdisk does not support gpt (guid partition table). I thought sfdisk did support gpt? It says to use parted, but i cant find a command that copies a partition table over from another disk in parted documentation. Any suggestions? I suppose i could make the partitions manually, but im writing a procedure for people who arent that technical and i need it to be simple enough to be run in my absence. manually building the partitions would be too hard for them.
I'm running 10.04 x86 server with a really simple installation on a single 250GB boot disk. I then have a RAID5 array as /dev/md0 (set up using mdadm with x4 2TB disks). All is working well. My mdadm.conf file looks like this
# mdadm.conf # # Please refer to mdadm.conf(5) for information about this file.
if I was to lose the boot disk and need to remount the RAID array on a fresh installation, what steps do I need to go through. My assumption is that the superblocks on the RAID disks will be used and I don't need to keep any additional information - is this right?
I've been having some problems w/ a my RAID 5 array, and after extensive investigation, I'm fairly sure that my last resort is rebuilding the array. I'd tried --assemble, b/c it's a previously created array, but it didn't seem to like that. So, I checked into --create, and it will re-create the array w/out destroying the data, if the superblocks are persistent, which they seem to be. However, here's what I get:
My question is: why do /dev/sdb1 and /dev/sdi1 show as both ext2fs and also as part of a RAID array?
I'm looking for advise on which drives to add into my server for software raid 5. I would like to use 2TB drives for the array. The server currently boots off a RAID 1 array and I have a couple other drives mounted until I build a RAID 5 array with new drives. I've read horror stories on using Western Digital WD20EARS and Seagate ST32000542AS. So I'm wondering which large drives are best to use in software raid?
I have a large RAID array of 12 TB attached to one of my Ubuntu server machines. The RAID volume is formatted with NTFS. The problem is that I can not mount this volume in Ubuntu. I can read it normally if I attach it to windows machine.This is the output from "sudo fdisk -l":
I have a total of 4 hdd's, 500gb 7.2rpm that I would like mirrored using raid 10. As you can see from the image, ubuntu 9.10 server isn't recognizing the full 2tb's. In fact, I'm not even sure about the configuration as I was thinking the HDD's would come up as four 500gb hdds. Instead I have the configuration above set and ready for Ubuntu to be installed on.
1. Is this typical of a server pre-configured from Dell(perc6 raid controller.
2.Why is ubuntu not recognizing the full capacity of the drives especially when it's a server install?
This is a strange problem. I have Ubuntu server installed on a proper server hardware. My RAID card reports all four HDDs to ubuntu as single drives, which is how i set it up because Ubuntu does not recognize the raid card on the server. Now you might say if thats the case, why dont i remove the raid card and have the BIOS report to ubuntu as four single drives then i can perhaps setup software raid. Well my board has only one sata port.Ubuntu is all setup. on the first drive and i have set the other three up using software RAID.
System works great only problem is it freezes sometimes. Not everytime, just on the odd occassion I use the same Hardware without the raid card and of course just one HDD and it great. No freezes.That leads me to believe its the RAID card.My question is why will it run great for days and sometimes just freeze on me? Probably silly but if theres an issue with the RAID card, it should not work at all, should it?