From c5afe3257dc95f9f5cbb7a9f04d2ad2d0e81bc3a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Antoine=20Beaupr=C3=A9?= <anarcat@debian.org>
Date: Fri, 10 Mar 2023 11:54:54 -0500
Subject: [PATCH] some notes on tape backups

AKA "why we don't (currently) do tape backups"
---
 howto/backup.md | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/howto/backup.md b/howto/backup.md
index 2bd4f9be..916cbf4d 100644
--- a/howto/backup.md
+++ b/howto/backup.md
@@ -1401,3 +1401,29 @@ TODO: populate Discussion section.
 ## Alternatives considered
 
 <!-- include benchmarks and procedure if relevant -->
+
+### Tape medium
+
+Last I (anarcat) checked, the latest (published) LTO tape standard
+stored a whopping 18TB of data, uncompressed, per cartridge and writes
+400MB/s which means it takes 12h30m to fill up one tape.
+
+LTO tapes are pretty cheap, e.g. [here is a 12TB LTO8 tape from Fuji
+for 80$CAD](https://www.newegg.ca/p/12K-00EM-00011). The LTO tape *drives* are however prohibitively
+expensive. For example, an "[upgrade kit](https://www.newegg.ca/hp-q6q68a-lto-ultrium-7-lto-ultrium-8/p/1HZ-00DX-00040)" for an HP tape library
+sells for a whopping 7k$CAD here. I can't actually find any LTO-8 tape
+drives on newegg.ca.
+
+As a comparison, you can get a [18TB Seagate IronWolf drive for
+410$CAD](https://www.newegg.ca/seagate-st18000ne000-18tb/p/N82E16822184872 ), which means for the price of that upgrade kit you can get
+a whopping 300TB worth of HDDs for the price of the *tape drive*.  And
+you don't have any actual tape yet, you'd need to shell out another
+2k$CAD to get 300TB of 12TB tapes.
+
+(Of course, that abstracts away the cost of running those hard
+drives. You might dodge that issue by pretending you can use HDD
+"trays" and hot-swap those drives around though, since that is
+effectively how tapes work. So maybe for the cost of that 2k$ of
+tapes, you could buy a 4U server with a bunch of slots for the hard
+drive, which you would *still* need to do to host the tape drive
+anyway.)
-- 
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