I just bought a LenovoEMC / IOmega IX2-dl NAS box (cheap, of course). It has a pair of WD Green 2T disk drives. The supplied firmware is Linux, of course. With a pretty face. /proc/cpuid says "Feroceon 88FR131 rev 1 (v5l)" which I think is an unfortunately old ARM family. It has 256M of RAM. The kernel is "2.6.31.8". It offers me RAID 1, RAID 0, and "none". I don't think that I want either RAID and I'm not sure what "none" is. I don't want RAID 1 because It doesn't give me much reliability improvement for the price (halving the space) and it doesn't give me any speed improvement. I don't want RAID 0 since it gives me less reliability than no RAID. I want two different filesystems so that when one goes south, the other isn't lost. Any advice on how to lightly prod this system to do what I want? Here's some configuration information. /etc/fstab doesn't mention the hard drives First, here's how it looks with the RAID1 setup. lsblk(8) says. (This command is new to me. I think that I like it): NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT loop0 7:0 0 680.4M 1 loop /mnt/apps loop1 7:1 0 8M 0 loop /mnt/etc loop2 7:2 0 100K 0 loop /oem sda 8:0 0 1.8T 0 disk ├─sda1 8:1 0 20G 0 part │ └─md0 9:0 0 20G 0 raid1 │ ├─md0_vg-BFDlv (dm-0) 253:0 0 4G 0 lvm /boot │ └─md0_vg-vol1 (dm-1) 253:1 0 16G 0 lvm /mnt/system └─sda2 8:2 0 1.8T 0 part └─md1 9:1 0 1.8T 0 raid1 └─6366c931_vg-lv163c50af (dm-2) 253:2 0 1.8T 0 lvm /mnt/pools/A/A0 sdb 8:16 0 1.8T 0 disk ├─sdb1 8:17 0 20G 0 part │ └─md0 9:0 0 20G 0 raid1 │ ├─md0_vg-BFDlv (dm-0) 253:0 0 4G 0 lvm /boot │ └─md0_vg-vol1 (dm-1) 253:1 0 16G 0 lvm /mnt/system └─sdb2 8:18 0 1.8T 0 part └─md1 9:1 0 1.8T 0 raid1 └─6366c931_vg-lv163c50af (dm-2) 253:2 0 1.8T 0 lvm /mnt/pools/A/A0 mtdblock0 31:0 0 504K 0 disk mtdblock1 31:1 0 4K 0 disk mtdblock2 31:2 0 4K 0 disk df(1) says: Filesystem 1K-blocks Used Available Use% Mounted on rootfs 51200 4216 46984 9% / /dev/root.old 11339 3185 8154 29% /initrd none 51200 4216 46984 9% / /dev/md0_vg/BFDlv 4128448 714776 3203960 19% /boot /dev/loop0 691776 619873 71903 90% /mnt/apps /dev/loop1 7657 1010 6238 14% /mnt/etc none 7657 1010 6238 14% /etc /dev/loop2 128 128 0 100% /oem tmpfs 24776 80 24696 1% /run tmpfs 5120 4 5116 1% /run/lock tmpfs 49540 0 49540 0% /run/shm /dev/mapper/md0_vg-vol1 16493480 975280 15350636 6% /mnt/system /dev/mapper/6366c931_vg-lv163c50af 1902053516 202188 1901851328 1% /mnt/pools/A/A0 /dev/mapper/6366c931_vg-lv163c50af 1902053516 202188 1901851328 1% /nfs/Backups /dev/mapper/6366c931_vg-lv163c50af 1902053516 202188 1901851328 1% /nfs/Documents /dev/mapper/6366c931_vg-lv163c50af 1902053516 202188 1901851328 1% /nfs/Movies /dev/mapper/6366c931_vg-lv163c50af 1902053516 202188 1901851328 1% /nfs/Music /dev/mapper/6366c931_vg-lv163c50af 1902053516 202188 1901851328 1% /nfs/SharedMedia /dev/mapper/6366c931_vg-lv163c50af 1902053516 202188 1901851328 1% /nfs/Pictures After I switched from RAID1 to "none": NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT loop0 7:0 0 680.4M 1 loop /mnt/apps loop1 7:1 0 8M 0 loop /mnt/etc loop2 7:2 0 100K 0 loop /oem sda 8:0 0 1.8T 0 disk ├─sda1 8:1 0 20G 0 part │ └─md0 9:0 0 20G 0 raid1 │ ├─md0_vg-BFDlv (dm-0) 253:0 0 4G 0 lvm /boot │ └─md0_vg-vol1 (dm-1) 253:1 0 16G 0 lvm /mnt/system └─sda2 8:2 0 1.8T 0 part └─md1 9:1 0 3.6T 0 linear └─529a853a_vg-lv1ac0e3be (dm-2) 253:2 0 3.6T 0 lvm /mnt/pools/A/A0 sdb 8:16 0 1.8T 0 disk ├─sdb2 8:18 0 1.8T 0 part │ └─md1 9:1 0 3.6T 0 linear │ └─529a853a_vg-lv1ac0e3be (dm-2) 253:2 0 3.6T 0 lvm /mnt/pools/A/A0 └─sdb1 8:17 0 20G 0 part └─md0 9:0 0 20G 0 raid1 ├─md0_vg-BFDlv (dm-0) 253:0 0 4G 0 lvm /boot └─md0_vg-vol1 (dm-1) 253:1 0 16G 0 lvm /mnt/system mtdblock0 31:0 0 504K 0 disk mtdblock1 31:1 0 4K 0 disk mtdblock2 31:2 0 4K 0 disk Filesystem 1K-blocks Used Available Use% Mounted on rootfs 51200 4264 46936 9% / /dev/root.old 11339 3185 8154 29% /initrd none 51200 4264 46936 9% / /dev/md0_vg/BFDlv 4128448 714776 3203960 19% /boot /dev/loop0 691776 619873 71903 90% /mnt/apps /dev/loop1 7657 1013 6235 14% /mnt/etc none 7657 1013 6235 14% /etc /dev/loop2 128 128 0 100% /oem tmpfs 24776 80 24696 1% /run tmpfs 5120 4 5116 1% /run/lock tmpfs 49540 0 49540 0% /run/shm /dev/mapper/md0_vg-vol1 16493480 975516 15350400 6% /mnt/system /dev/mapper/529a853a_vg-lv1ac0e3be 3804366528 200884 3804165644 1% /mnt/pools/A/A0
| From: D. Hugh Redelmeier <hugh@mimosa.com> | It offers me RAID 1, RAID 0, and "none". I don't think that I want | either RAID and I'm not sure what "none" is. Here's an explanation: ● Mirror (RAID 1) Uses half of the storage space for protection, leaving half for actual data. ● None (RAID 0) Uses all of the storage space for data. Does not protect against data loss in the event of drive failure; however, the drives are striped for better performance. ● None Uses all of the storage space for data, providing contiguous storage space by concatenating all member drives. Does not protect against data loss in the event of drive failure. So none of these choices do what I want. I might be willing to give up half the space if there were a feature like Windows Home Server's "folder duplication". I think that this duplicates files on a different volume.
Sounds to me like "none" is the same as RAID 0, save for the difference surrounding striping. The *lack* of ability to treat this as a device per drive is why I'd be not too keen on buying one of these devices. I'd prefer to have what is commonly called "JBOD" support, ("Just a Bunch Of Drives") and of the form where each drive is treated as a separate device on the array. To me, not having that is a deal breaker.
On Thu, Feb 19, 2015 at 4:12 PM, D. Hugh Redelmeier <hugh@mimosa.com> wrote:
| From: D. Hugh Redelmeier <hugh@mimosa.com>
| It offers me RAID 1, RAID 0, and "none". I don't think that I want | either RAID and I'm not sure what "none" is.
Here's an explanation:
● Mirror (RAID 1) Uses half of the storage space for protection, leaving half for actual data. ● None (RAID 0) Uses all of the storage space for data. Does not protect against data loss in the event of drive failure; however, the drives are striped for better performance. ● None Uses all of the storage space for data, providing contiguous storage space by concatenating all member drives. Does not protect against data loss in the event of drive failure.
So none of these choices do what I want.
I might be willing to give up half the space if there were a feature like Windows Home Server's "folder duplication". I think that this duplicates files on a different volume.
Why not use RAID10 so you have striped AND mirrored. That should give you your performance and some security. (One can always have more security!) Haven't had any issue but a single drive failure (that I've just gotten a replacement drive for and am working on its implementation into the array) in three years. I've not had any issues with speed nor capacity. (My array is 4 1TB drives.) YMMV Dee
Looks like each disk has 2 partitions, /dev/sd[ab]1 --> /dev/md0 --> raid1 (1.8TB) /dev/sd[ab]2 --> /dev/md1 --> raid1 (1.8TB) or linear (3.6TB) So, "none" is linear array. Strange, because "none" is usually individual drive, and it usually says "linear" if it is linear. -- William On Thu, Feb 19, 2015 at 04:56:12PM -0500, D. Hugh Redelmeier wrote:
I just bought a LenovoEMC / IOmega IX2-dl NAS box (cheap, of course). It has a pair of WD Green 2T disk drives.
The supplied firmware is Linux, of course. With a pretty face.
/proc/cpuid says "Feroceon 88FR131 rev 1 (v5l)" which I think is an unfortunately old ARM family. It has 256M of RAM. The kernel is "2.6.31.8".
It offers me RAID 1, RAID 0, and "none". I don't think that I want either RAID and I'm not sure what "none" is.
I don't want RAID 1 because It doesn't give me much reliability improvement for the price (halving the space) and it doesn't give me any speed improvement.
I don't want RAID 0 since it gives me less reliability than no RAID.
I want two different filesystems so that when one goes south, the other isn't lost.
Any advice on how to lightly prod this system to do what I want?
Here's some configuration information.
/etc/fstab doesn't mention the hard drives
First, here's how it looks with the RAID1 setup.
lsblk(8) says. (This command is new to me. I think that I like it):
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT loop0 7:0 0 680.4M 1 loop /mnt/apps loop1 7:1 0 8M 0 loop /mnt/etc loop2 7:2 0 100K 0 loop /oem sda 8:0 0 1.8T 0 disk ??sda1 8:1 0 20G 0 part ? ??md0 9:0 0 20G 0 raid1 ? ??md0_vg-BFDlv (dm-0) 253:0 0 4G 0 lvm /boot ? ??md0_vg-vol1 (dm-1) 253:1 0 16G 0 lvm /mnt/system ??sda2 8:2 0 1.8T 0 part ??md1 9:1 0 1.8T 0 raid1 ??6366c931_vg-lv163c50af (dm-2) 253:2 0 1.8T 0 lvm /mnt/pools/A/A0 sdb 8:16 0 1.8T 0 disk ??sdb1 8:17 0 20G 0 part ? ??md0 9:0 0 20G 0 raid1 ? ??md0_vg-BFDlv (dm-0) 253:0 0 4G 0 lvm /boot ? ??md0_vg-vol1 (dm-1) 253:1 0 16G 0 lvm /mnt/system ??sdb2 8:18 0 1.8T 0 part ??md1 9:1 0 1.8T 0 raid1 ??6366c931_vg-lv163c50af (dm-2) 253:2 0 1.8T 0 lvm /mnt/pools/A/A0 mtdblock0 31:0 0 504K 0 disk mtdblock1 31:1 0 4K 0 disk mtdblock2 31:2 0 4K 0 disk
df(1) says:
Filesystem 1K-blocks Used Available Use% Mounted on rootfs 51200 4216 46984 9% / /dev/root.old 11339 3185 8154 29% /initrd none 51200 4216 46984 9% / /dev/md0_vg/BFDlv 4128448 714776 3203960 19% /boot /dev/loop0 691776 619873 71903 90% /mnt/apps /dev/loop1 7657 1010 6238 14% /mnt/etc none 7657 1010 6238 14% /etc /dev/loop2 128 128 0 100% /oem tmpfs 24776 80 24696 1% /run tmpfs 5120 4 5116 1% /run/lock tmpfs 49540 0 49540 0% /run/shm /dev/mapper/md0_vg-vol1 16493480 975280 15350636 6% /mnt/system /dev/mapper/6366c931_vg-lv163c50af 1902053516 202188 1901851328 1% /mnt/pools/A/A0 /dev/mapper/6366c931_vg-lv163c50af 1902053516 202188 1901851328 1% /nfs/Backups /dev/mapper/6366c931_vg-lv163c50af 1902053516 202188 1901851328 1% /nfs/Documents /dev/mapper/6366c931_vg-lv163c50af 1902053516 202188 1901851328 1% /nfs/Movies /dev/mapper/6366c931_vg-lv163c50af 1902053516 202188 1901851328 1% /nfs/Music /dev/mapper/6366c931_vg-lv163c50af 1902053516 202188 1901851328 1% /nfs/SharedMedia /dev/mapper/6366c931_vg-lv163c50af 1902053516 202188 1901851328 1% /nfs/Pictures
After I switched from RAID1 to "none":
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT loop0 7:0 0 680.4M 1 loop /mnt/apps loop1 7:1 0 8M 0 loop /mnt/etc loop2 7:2 0 100K 0 loop /oem sda 8:0 0 1.8T 0 disk ??sda1 8:1 0 20G 0 part ? ??md0 9:0 0 20G 0 raid1 ? ??md0_vg-BFDlv (dm-0) 253:0 0 4G 0 lvm /boot ? ??md0_vg-vol1 (dm-1) 253:1 0 16G 0 lvm /mnt/system ??sda2 8:2 0 1.8T 0 part ??md1 9:1 0 3.6T 0 linear ??529a853a_vg-lv1ac0e3be (dm-2) 253:2 0 3.6T 0 lvm /mnt/pools/A/A0 sdb 8:16 0 1.8T 0 disk ??sdb2 8:18 0 1.8T 0 part ? ??md1 9:1 0 3.6T 0 linear ? ??529a853a_vg-lv1ac0e3be (dm-2) 253:2 0 3.6T 0 lvm /mnt/pools/A/A0 ??sdb1 8:17 0 20G 0 part ??md0 9:0 0 20G 0 raid1 ??md0_vg-BFDlv (dm-0) 253:0 0 4G 0 lvm /boot ??md0_vg-vol1 (dm-1) 253:1 0 16G 0 lvm /mnt/system mtdblock0 31:0 0 504K 0 disk mtdblock1 31:1 0 4K 0 disk mtdblock2 31:2 0 4K 0 disk
Filesystem 1K-blocks Used Available Use% Mounted on rootfs 51200 4264 46936 9% / /dev/root.old 11339 3185 8154 29% /initrd none 51200 4264 46936 9% / /dev/md0_vg/BFDlv 4128448 714776 3203960 19% /boot /dev/loop0 691776 619873 71903 90% /mnt/apps /dev/loop1 7657 1013 6235 14% /mnt/etc none 7657 1013 6235 14% /etc /dev/loop2 128 128 0 100% /oem tmpfs 24776 80 24696 1% /run tmpfs 5120 4 5116 1% /run/lock tmpfs 49540 0 49540 0% /run/shm /dev/mapper/md0_vg-vol1 16493480 975516 15350400 6% /mnt/system /dev/mapper/529a853a_vg-lv1ac0e3be 3804366528 200884 3804165644 1% /mnt/pools/A/A0
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On Fri, Feb 20, 2015 at 12:10:45AM -0500, William Park wrote:
Looks like each disk has 2 partitions, /dev/sd[ab]1 --> /dev/md0 --> raid1 (1.8TB)
Typo.......................................^^^^^\__ 20GB
/dev/sd[ab]2 --> /dev/md1 --> raid1 (1.8TB) or linear (3.6TB) So, "none" is linear array. Strange, because "none" is usually individual drive, and it usually says "linear" if it is linear.
On Thu, Feb 19, 2015 at 04:56:12PM -0500, D. Hugh Redelmeier wrote:
I just bought a LenovoEMC / IOmega IX2-dl NAS box (cheap, of course). It has a pair of WD Green 2T disk drives.
The supplied firmware is Linux, of course. With a pretty face.
/proc/cpuid says "Feroceon 88FR131 rev 1 (v5l)" which I think is an unfortunately old ARM family. It has 256M of RAM. The kernel is "2.6.31.8".
It offers me RAID 1, RAID 0, and "none". I don't think that I want either RAID and I'm not sure what "none" is.
I don't want RAID 1 because It doesn't give me much reliability improvement for the price (halving the space) and it doesn't give me any speed improvement.
I don't want RAID 0 since it gives me less reliability than no RAID.
I want two different filesystems so that when one goes south, the other isn't lost.
I suspect none in fact means make each disk seperate. But it might not. It could be that they mean: RAID1: Mirror two identical disks RAID0: Stripe data across two identical disks for speed none: Concat the disks into one large disk, without added safety or speed gains.
Any advice on how to lightly prod this system to do what I want?
Here's some configuration information.
/etc/fstab doesn't mention the hard drives
First, here's how it looks with the RAID1 setup.
lsblk(8) says. (This command is new to me. I think that I like it):
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT loop0 7:0 0 680.4M 1 loop /mnt/apps loop1 7:1 0 8M 0 loop /mnt/etc loop2 7:2 0 100K 0 loop /oem sda 8:0 0 1.8T 0 disk ├─sda1 8:1 0 20G 0 part │ └─md0 9:0 0 20G 0 raid1 │ ├─md0_vg-BFDlv (dm-0) 253:0 0 4G 0 lvm /boot │ └─md0_vg-vol1 (dm-1) 253:1 0 16G 0 lvm /mnt/system └─sda2 8:2 0 1.8T 0 part └─md1 9:1 0 1.8T 0 raid1 └─6366c931_vg-lv163c50af (dm-2) 253:2 0 1.8T 0 lvm /mnt/pools/A/A0 sdb 8:16 0 1.8T 0 disk ├─sdb1 8:17 0 20G 0 part │ └─md0 9:0 0 20G 0 raid1 │ ├─md0_vg-BFDlv (dm-0) 253:0 0 4G 0 lvm /boot │ └─md0_vg-vol1 (dm-1) 253:1 0 16G 0 lvm /mnt/system └─sdb2 8:18 0 1.8T 0 part └─md1 9:1 0 1.8T 0 raid1 └─6366c931_vg-lv163c50af (dm-2) 253:2 0 1.8T 0 lvm /mnt/pools/A/A0 mtdblock0 31:0 0 504K 0 disk mtdblock1 31:1 0 4K 0 disk mtdblock2 31:2 0 4K 0 disk
df(1) says:
Filesystem 1K-blocks Used Available Use% Mounted on rootfs 51200 4216 46984 9% / /dev/root.old 11339 3185 8154 29% /initrd none 51200 4216 46984 9% / /dev/md0_vg/BFDlv 4128448 714776 3203960 19% /boot /dev/loop0 691776 619873 71903 90% /mnt/apps /dev/loop1 7657 1010 6238 14% /mnt/etc none 7657 1010 6238 14% /etc /dev/loop2 128 128 0 100% /oem tmpfs 24776 80 24696 1% /run tmpfs 5120 4 5116 1% /run/lock tmpfs 49540 0 49540 0% /run/shm /dev/mapper/md0_vg-vol1 16493480 975280 15350636 6% /mnt/system /dev/mapper/6366c931_vg-lv163c50af 1902053516 202188 1901851328 1% /mnt/pools/A/A0 /dev/mapper/6366c931_vg-lv163c50af 1902053516 202188 1901851328 1% /nfs/Backups /dev/mapper/6366c931_vg-lv163c50af 1902053516 202188 1901851328 1% /nfs/Documents /dev/mapper/6366c931_vg-lv163c50af 1902053516 202188 1901851328 1% /nfs/Movies /dev/mapper/6366c931_vg-lv163c50af 1902053516 202188 1901851328 1% /nfs/Music /dev/mapper/6366c931_vg-lv163c50af 1902053516 202188 1901851328 1% /nfs/SharedMedia /dev/mapper/6366c931_vg-lv163c50af 1902053516 202188 1901851328 1% /nfs/Pictures
After I switched from RAID1 to "none":
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT loop0 7:0 0 680.4M 1 loop /mnt/apps loop1 7:1 0 8M 0 loop /mnt/etc loop2 7:2 0 100K 0 loop /oem sda 8:0 0 1.8T 0 disk ├─sda1 8:1 0 20G 0 part │ └─md0 9:0 0 20G 0 raid1 │ ├─md0_vg-BFDlv (dm-0) 253:0 0 4G 0 lvm /boot │ └─md0_vg-vol1 (dm-1) 253:1 0 16G 0 lvm /mnt/system └─sda2 8:2 0 1.8T 0 part └─md1 9:1 0 3.6T 0 linear └─529a853a_vg-lv1ac0e3be (dm-2) 253:2 0 3.6T 0 lvm /mnt/pools/A/A0 sdb 8:16 0 1.8T 0 disk ├─sdb2 8:18 0 1.8T 0 part │ └─md1 9:1 0 3.6T 0 linear │ └─529a853a_vg-lv1ac0e3be (dm-2) 253:2 0 3.6T 0 lvm /mnt/pools/A/A0 └─sdb1 8:17 0 20G 0 part └─md0 9:0 0 20G 0 raid1 ├─md0_vg-BFDlv (dm-0) 253:0 0 4G 0 lvm /boot └─md0_vg-vol1 (dm-1) 253:1 0 16G 0 lvm /mnt/system mtdblock0 31:0 0 504K 0 disk mtdblock1 31:1 0 4K 0 disk mtdblock2 31:2 0 4K 0 disk
That does in fact look like with none as the setting, it is just adding each disk to the volumegroup for the pool. It would seem with this design, the only option that will tolerate disk failures is RAID1. The others will have complete data loss if any disk fails. RAID0 gives extra speed but requires identical disks, while none does not give extra speed and allows different disk sizes to be in use. -- Len Sorensen
participants (5)
-
Christopher Browne -
D. Hugh Redelmeier -
Lennart Sorensen -
o1bigtenor -
William Park