Both halves of the mirror had bad sectors - combining the good sectors from each rebuilt a complete image.
A small business ran its server on a two-disk RAID 1 mirror, in the reasonable belief that the mirror was its backup. The trouble was that both disks had quietly been developing bad sectors over the same period, and when one finally dropped out the other turned out to be unreadable in places too. With neither disk fully readable on its own, the array failed and there was no clean copy on either side — the very redundancy the mirror was supposed to provide had been eroded on both halves at once.
We assessed both disks individually. Each was failing with bad sectors, but — crucially — they were not failing in the same places. A mirror means the two disks hold identical data, which works strongly in our favour here: a sector that is unreadable on one disk is very often perfectly readable on the other, so between the pair a complete copy can usually be assembled.
We imaged both members on DeepSpar Disk Imagers, capturing as much as each could give and noting precisely which sectors each one failed on, with the PC3000 for firmware-level work. We then merged the two images — taking each good sector from whichever disk could supply it — to reconstruct a single, complete image of the volume. Where one disk had a gap, the other almost always filled it, and the combined image came together cleanly.
From the merged image we rebuilt the file system, confirmed the business's data opened correctly, and returned everything on fresh media.
Between the two ailing disks we reassembled a full, clean copy of the volume and returned all of the business's data, five working days on. The lesson is an important and often-missed one: a mirror protects against one disk failing suddenly, but if both disks are the same age and degrade together it offers far less protection than it appears to — which is why a RAID still needs a separate backup, and why disks are worth monitoring for early signs of wear.
DeepSpar DDI · PC3000 — imaging and recovery carried out in-house. Every job is imaged before any recovery work begins, and the original media is never written to.
Send us your device for a free diagnostic, and tell us a little about what happened — an engineer will review it and confirm your exact quote in writing before any work begins.
Recovering your data starts with getting the device to us. Pack it safely, add your contact details, and send it over — after we run a free diagnostic, we’ll confirm your exact price in writing before any work begins.
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Yes — any level, controller or failed rebuild. We image every member disk read-only, recover the parameters, and reconstruct the array virtually from the copies.
From £500 plus VAT, no fix, no fee on most jobs, with a fixed quote up front; emergency, round-the-clock service is available.
No. A failed rebuild is the most common cause of permanent loss. Stop, remove the drives labelled with their bay order, and send them to us.
Start with an instant online quote, or call and talk it through with us first. You'll have a clear, fixed price before any work begins.