Hello all. I have a simple network storage system with a boot drive and two large storage drives. Originally it had just one drive and everything was hunky dory until I added the second drive, which was previously an external backup. I ran fdisk -l to look at the newly added drive and saw errors on both disks. I remember something like "GPT PMBR size mismatch" and it telling me to use the write command in gdisk.

After looking up similar things on the internet it seemed like running the write command by itself should have fixed things. Thing is, I did not exactly do that. On the first disk (sda) I ran verify and then write on its partition (sda1). That I believe was a mistake and was from not paying attention to what I was doing. On the other drive (sdb) I ran verify and write.

As it stands now I cannot use either drive. When I look at them on a different system using fdisk -l one shows up with no partitions and the other shows up with a partition but I cannot manually mount it. I considered running fsck on either one but I'm in uncharted territory there and afraid I'll do more damage.

"GPT PMBR size mismatch" suggests that your disks were formatted as GPT and not MBR. The Pseudo-MBR size warning could have been ignored since MBR does not support large drive sizes. GPT support is a recent addition to fdisk and results in the misleading messages. Boot from a live-iso image or look on a different system at the real partition tables with:

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Thanks for the info, I will post the results once I get home.

Parted so shows two disks with GPT partition tables, but only one drive has an entry under disk flags. All other information about the disks looks okay. If it makes any difference, both drives only had one partition spanning the entire volume.