diff --git a/content/1.md b/content/1.md index a27d667..393ff17 100644 --- a/content/1.md +++ b/content/1.md @@ -6,7 +6,7 @@ type = "post" class="post first" +++ -It is a common technique to provide **resiliency** and **availability** to a set of data and protect against one of the most common data loss scenarios: the failure of a disk. +It is a common technique to provide *resiliency* and *availability* to a set of data and protect against one of the most common data loss scenarios: the failure of a disk. The simplest type of RAID is a 'mirror', which does just what it sounds like: keeps two (or more) copies of data on two (or more) different disks. If one disk fails, the second copy is still available and no data loss has occurred. diff --git a/content/2.md b/content/2.md index 037bf36..38df493 100644 --- a/content/2.md +++ b/content/2.md @@ -5,11 +5,11 @@ weight = 2 type = "post" +++ -Having a number of disks in RAID may **seem** like a backup, especially if you're using a mirror mode. But this is **wrong**! +Having a number of disks in RAID may *seem* like a backup, especially if you're using a mirror mode. But this is *wrong*! RAID protects you against one and only one thing: a disk failure. -It does **not** protect you against any of the following things: +It does *not* protect you against any of the following things: * Multiple disk failures beyond the RAID level chosen (e.g. both disks in a mirror, or 3 disks in a RAID-6). * Failure of the RAID controller itself (especially when using hardware RAID), the computer running the RAID, or the environment (a flood, fire, theft, etc.). @@ -18,6 +18,6 @@ It does **not** protect you against any of the following things: Even ZFS, designed specifically to prevent the third point, is still susceptable to the others. -The adage is simple: "RAID replicates **everything**, instantly, even the stuff you don't want." Like the deletion of a file or corruption. +The adage is simple: "RAID replicates *everything*, instantly, even the stuff you don't want." Like the deletion of a file or corruption. For these reasons and more, RAID IS NOT A BACKUP! diff --git a/content/3.md b/content/3.md index 9c841b9..a04d8ab 100644 --- a/content/3.md +++ b/content/3.md @@ -5,11 +5,11 @@ weight = 3 type = "post" +++ -* Always back up in **some way**. While a copy of the data on the same array won't protect you against all problems, it will protect you against some. -* A **backup on the same server** is susceptable to the **same failures as the original data** set (hardware failure, natural disasters, and the like). -* A good rule of thumb is **three copies** (the RAID is only one copy for this purpose): the **original**, one **onsite copy**, and one **offsite copy**. Store the offsite copy in the cloud, or at a friend's house. -* **Make backups regularly**, at least once a week; the day you need a backup is the day you realize you hadn't run it in 6 months and what you need isn't backed up. -* **Test backups regularly**, at least once a month; **a backup is worthless if you can't restore from it**. Just because you have a backup doesn't mean you're protected; always test them. +* Always back up in *some way*. While a copy of the data on the same array won't protect you against all problems, it will protect you against some. +* A *backup on the same server* is susceptable to the *same failures as the original data* set (hardware failure, natural disasters, and the like). +* A good rule of thumb is *three copies* (the RAID is only one copy for this purpose): the *original*, one *onsite copy*, and one *offsite copy*. Store the offsite copy in the cloud, or at a friend's house. +* *Make backups regularly*, at least once a week; the day you need a backup is the day you realize you hadn't run it in 6 months and what you need isn't backed up. +* *Test backups regularly*, at least once a month; *a backup is worthless if you can't restore from it*. Just because you have a backup doesn't mean you're protected; always test them. There are dozens of backup utilities out there; I'm not going to prosthelytize for any one of them, but I personally use [BackupPC](http://backuppc.sourceforge.net/) for my server and workstation backups.