I have had 4 external drives connected over USB to my Dell Precision 490 workstation.
They are in /etc/fstab by uuid and formated as UUID.
UUID=04c37bff-b93e-440e-acd0-3d984ddb2ec3 /mnt/drive0 ext4 defaults,nobootwait 0 2
UUID=210765f4-30e5-4863-a40b-aa1fffefe5ca /mnt/drive1 ext4 defaults,nobootwait 0 2
UUID=b981c5e7-249e-4430-9887-96ca674e0733 /mnt/drive2 ext4 defaults,nobootwait 0 2
UUID=22c8a274-3cf9-403f-9558-feb531e407c7 /mnt/drive3 ext4 defaults,nobootwait 0 2
I put three drives inside but only one mounts automatically (drive3, drive2 is still connected externally)
$ mount | grep /dev/sd
/dev/sdc1 on /boot type ext2 (rw)
/dev/sdb1 on /mnt/drive3 type ext4 (rw)
/dev/sdf1 on /mnt/drive2 type ext4 (rw)
But they all show up:
$ sudo fdisk -l
WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted.
Disk /dev/sda: 120.0 GB, 120034123776 bytes
<snip>
Disk /dev/sdb: 5001.0 GB, 5000981078016 bytes
255 heads, 63 sectors/track, 608001 cylinders, total 9767541168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0xdd494cbf
Device Boot Start End Blocks Id System
/dev/sdb1 1 4294967295 2147483647+ ee GPT
Partition 1 does not start on physical sector boundary.
Disk /dev/sdd: 5001.0 GB, 5000981078016 bytes
42 heads, 62 sectors/track, 3750975 cylinders, total 9767541168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0xec15dda8
Device Boot Start End Blocks Id System
/dev/sdd1 256 1220942644 610471194+ 83 Linux
Disk /dev/sde: 5001.0 GB, 5000981078016 bytes
255 heads, 63 sectors/track, 608001 cylinders, total 9767541168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x4cd5215a
Device Boot Start End Blocks Id System
/dev/sde1 63 1220942644 610471291 83 Linux
Partition 1 does not start on physical sector boundary.
Disk /dev/sdc: 500.1 GB, 500107862016 bytes
<snip>
Disk /dev/sdf: 5001.0 GB, 5000981073920 bytes
255 heads, 63 sectors/track, 76000 cylinders, total 1220942645 sectors
Units = sectors of 1 * 4096 = 4096 bytes
Sector size (logical/physical): 4096 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x6b6805d9
Device Boot Start End Blocks Id System
/dev/sdf1 63 1220942644 588803032 83 Linux
$ ls /dev/sd*
/dev/sda /dev/sda1 /dev/sdb /dev/sdb1 /dev/sdc /dev/sdc1 /dev/sdc2 /dev/sdc5 /dev/sdd /dev/sdd1 /dev/sde /dev/sde1 /dev/sdf /dev/sdf1
If I try to mount normally:
$ sudo mkdir /mnt/temp
$ sudo mount -t ext4 /dev/sde1 /mnt/temp
mount: wrong fs type, bad option, bad superblock on /dev/sde1,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so
$ dmesg | tail
[87143.301150] EXT4-fs (sde1): VFS: Can't find ext4 filesystem
[87295.537835] EXT4-fs (sde1): VFS: Can't find ext4 filesystem
[87315.780147] EXT4-fs (sde1): VFS: Can't find ext4 filesystem
[87315.780290] EXT4-fs (sde1): VFS: Can't find ext4 filesystem
[87315.780421] EXT4-fs (sde1): VFS: Can't find ext4 filesystem
The machine has 5 SATA ports, I also bought a PCIe SATA controller and tried that. No difference. Moving devices between ports still yields no difference. The two other drives always mount.
I put them back in their respective external cases with USB controllers and they worked. Although when I tried to use the case from one of the drives that did mount directly connected, it was not recognized.
Thanks!
Edit: Adding output from gdisk
$ sudo gdisk /dev/sde
GPT fdisk (gdisk) version 0.8.8
Partition table scan:
MBR: MBR only
BSD: not present
APM: not present
GPT: not present
***************************************************************
Found invalid GPT and valid MBR; converting MBR to GPT format
in memory. THIS OPERATION IS POTENTIALLY DESTRUCTIVE! Exit by
typing 'q' if you don't want to convert your MBR partitions
to GPT format!
***************************************************************
Command (? for help): p
Disk /dev/sde: 9767541168 sectors, 4.5 TiB
Logical sector size: 512 bytes
Disk identifier (GUID): 00C22148-8C82-4062-BEC5-6759E7E23856
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 9767541134
Partitions will be aligned on 8-sector boundaries
Total free space is 8546598519 sectors (4.0 TiB)
Number Start (sector) End (sector) Size Code Name
1 63 1220942644 582.2 GiB 8300 Linux filesystem
$ sudo gdisk /dev/sdb
GPT fdisk (gdisk) version 0.8.8
Partition table scan:
MBR: protective
BSD: not present
APM: not present
GPT: present
Found valid GPT with protective MBR; using GPT.
Command (? for help): p
Disk /dev/sdb: 9767541168 sectors, 4.5 TiB
Logical sector size: 512 bytes
Disk identifier (GUID): E76C335B-FBA1-4FE0-9DC2-C5CADBECA6B0
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 9767541133
Partitions will be aligned on 8-sector boundaries
Total free space is 0 sectors (0 bytes)
Number Start (sector) End (sector) Size Code Name
1 34 9767541133 4.5 TiB 8300 disk4
Interesting, looks like the disks that don't mount use MBR instead of GPT?
Best Answer
This sounds like the problem described at https://superuser.com/questions/679725/how-to-correct-512-byte-sector-mbr-on-a-4096-byte-sector-disk: the USB enclosures reported a different sector size than the motherboard, and as result the partition tables are interpreted differently.
I had a similar problem with a 4TB disk that I had moved from a USB enclosure to an internal SATA port. Apparently the USB enclosure had reported 4k sectors, and thus I was able to use an old-fashioned MBR partition table to create a 4TB ext4 partition. After connecting the disk via SATA, the ext4 partition wasn't found any more, apparently because the disk was accessed with 512B sectors now.
I got it solved with the following steps, using the Testdisk data recovery tool which is available in Ubuntu:
sfdisk -d /dev/sdb > sfdisk-sdb.txt
), for safetytestdisk /dev/sdb
to find the original ext4 file systemEXT4-fs (sdb1): bad geometry: block count 976751744 exceeds size of device (536870911 blocks)
gdisk /dev/sdb
to convert the MBR to GPT format, and write the GPT to disktestdisk /dev/sdb
again to find the original ext4 file system (it detected the wrong file system type but that didn't matter), and let it write a new GPT table to diskgdisk /dev/sdb
to change the incorrectly detected file system type to8300
Maybe I just got lucky, but after this procedure the ext4 file system could be mounted as usual.
fsck -f /dev/sdb1
didn't detect any errors, andblkid /dev/sdb1
andtune2fs /dev/sdb1
gave same results as when using the USB enclosure.