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It depends on your RAID controller. If you have a true hardware RAID controller then yes, the failed/failing drive can be removed and another drive take its place then start the raid rebuild. If the RAID controller is software based there will be downtime. <br />
<br />
Can you provide the RAID controller info?
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Depending on your disc controller if it supports hot-plug you can certainly add another drive and add it to the array as it now shows the md1 array if running only on one drive, the second seems to have failed.<br />
<br />
If you don't have hot-plug capability then I suggest you make backup of your server, shut it down, replace the second drive (sdb) restart machine and partition the new drive accordingly and add it to the array.
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I don't think so. You would first need to make an extra backup of the data disk, and I wouldn't do that with users using it which may change data that has already been backed up. You would also have to run an fsck on the working partitions on that disk to repair any file-system corruptions, and that needs to be done with the partitions unmounted.
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Hi<br />
<br />
I need an advise if possible for you guys. One of my servers is showing following:<br />
<br />
# cat /proc/mdstat <br />
Personalities : [raid1] <br />
md0 : active raid1 sda1[0] sdb1[1]<br />
&nbsp; &nbsp; &nbsp; 255936 blocks super 1.0 [2/2] [UU]<br />
&nbsp; &nbsp; &nbsp; <br />
md1 : active raid1 sda2[0]<br />
&nbsp; &nbsp; &nbsp; 976373760 blocks super 1.1 [2/1] [U_]<br />
&nbsp; &nbsp; &nbsp; bitmap: 5/8 pages [20KB], 65536KB chunk<br />
<br />
unused devices: &lt;none&gt;<br />
<br />
<br />
I can see the md1 is running on one drive only and this is the one where all the data resides.<br />
<br />
This seems risky to me. Can the other drive be added without a risk and reboot/downtime? This is a production server.
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Hi

I need an advise if possible for you guys. One of my servers is showing following:

# cat /proc/mdstat 
Personalities : [raid1] 
md0 : active raid1 sda1[0] sdb1[1]
      255936 blocks super 1.0 [2/2] [UU]
      
md1 : active raid1 sda2[0]
      976373760 blocks super 1.1 [2/1] [U_]
      bitmap: 5/8 pages [20KB], 65536KB chunk

unused devices: <none>


I can see the md1 is running on one drive only and this is the one where all the data resides.

This seems risky to me. Can the other drive be added without a risk and reboot/downtime? This is a production server.

RAID failing

Linux is a UNIX-like open source operating system with hundreds of distinct distributions, including: Fedora, openSUSE, Ubuntu, Debian, Slackware, Gentoo, CentOS, and Arch Linux. Linux is generally associated with web and database servers, but has become popular in many niche industries and applications.

Linux

A Linux distribution is an operating system made as a software collection based on the Linux kernel and, often, on a package management system and are available for a variety of systems. A typical Linux distribution comprises a Linux kernel, GNU tools and libraries, additional software, documentation, a window system (the most common being the X Window System), a window manager, and a desktop environment. Most Linux systems are open-source software made available both as compiled binaries and in source code form, allowing modifications to the original software. Over three hundred distributions are in active development, including commercially backed distributions (such as Fedora, openSUSE and Ubuntu) and community-driven distributions (such as Debian, Slackware, Gentoo and Arch Linux).

Linux Distributions

Computer data storage, often called storage or memory, is a technology consisting of computer components and recording media used to retain digital data. In addition to local storage devices like CD and DVD readers, hard drives and flash drives, solid state drives can hold enormous amounts of data in a very small device. Cloud services and other new forms of remote storage also add to the capacity of devices and their ability to access more data without building additional data storage into a device.

Storage

RAID stands for Redundant Array of Independent Disks.

RAID is data storage technology that allows multiple drives to be used together as a single virtual drive for reasons such as fault tolerance, reliability and performance. 

There are several different levels of RAID that determine how the data is stored and the level of redundancy achieved across the drives.