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Understanding RAID: How performance scales from one disk to eight:
One of the first big challenges neophyte sysadmins and data hoarding enthusiasts face is how to store more than a single disk worth of data. The short—and traditional—answer here is RAID (a Redundant Array of Inexpensive Disks), but even then there are many different RAID topologies to choose from.
Most people who implement RAID expect to get extra performance, as well as extra storage, out of all those disks. Those expectations aren't always rooted very firmly in the real world, unfortunately. But since we're all home with time for some technical projects, we hope to shed some light on how to plan for storage performance—not just the total number of gibibytes (GB) you can cram into an array.
A quick note here: Although readers will be interested in the raw numbers, we urge a stronger focus on how they relate to one another. All of our charts relate the performance of RAID arrays at sizes from two to eight disks to the performance of a single disk. If you change the model of disk, your raw numbers will change accordingly—but the relation to a single disk's performance will not for the most part.
[...] For all tests, we're using Linux kernel RAID, as implemented in the Linux kernel version 4.15, along with the ext4 filesystem. We used the --assume-clean parameter when creating our RAID arrays in order to avoid overwriting every block of the array, and we used -E lazy_itable_init=0,lazy_journal_init=0 when creating the ext4 filesystem to avoid contaminating our tests with ongoing background writes initializing the filesystem in the background.
(Score: 0) by Anonymous Coward on Tuesday April 21 2020, @01:47AM (1 child)
RAID-1 is probably the most cost-effective back-up scheme.
Basically, you use three drives for a single volume. Two for redundancy, the third as a backup. Rotate the three periodically.
Slow tapes are impractical, particularly with the petabytes capacities today.
(Score: 2) by mmh on Thursday April 23 2020, @11:35PM
As a Linax Systems Expert, I concur! RAID, any level (raid zero is actually the best choice here because 0 is smaller than 1 and thus requires less computational power.), is an excellent replacement for backups!
Although two disks is really just unnecessary expense. Take one disk, put two partitions on it, and RAID1 those together! Redundancy and cost savings! If you're really paranoid, you could do three partitions, but then you need to buy a bigger disk, and that costs more, so I don't really like to do that unless the client wants to spare no expense.