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--- selfhost:storage [2024/02/07 10:53] – willy
+++ selfhost:storage [Unknown date] (current) – removed - external edit (Unknown date) 127.0.0.1
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-===== Storage Setup =====
-You have already installed your Gentoo Linux, fresh and nice. Now it's time to organize and setup the storage.
-First of all: the disk/partition on which the operating system is installed must be separated from where you will store your data and your services. The basic idea is that if you will need to migrate your services and data to a new server, for an upgrade or a failure, all it will take is reinstalling the OS and re-plugging the storage drives.
-The best approach is to use one drive for the OS and different drives (usually at least 2) for your data and services. These drives should be physically separated drives, and not different partitions on the same drive.
-So you will have your **OS** drive and your **services** drive (which will include also the data).
-//note:// having data and services on the same drive ensures that you can perform hard-links, which in some cases are mandatory to avoid data duplication (i am talking about torrents).
-The idea is to store your **services** on a redundant software RAID-1 array. Now, there are different solutions you can choose from. You could go RAID-5, RAID-0+1, RAID-6, RAID-10 and many more combinations. I will let you research and find out what works best for your use case and drives availability.
-RAID-1 has a few advantages for me which are:
-  * Good balance with wasted disk space (50% wasted)
-  * Fast enough on read (reads will be balanced on both disks, writes will take slightly longer)
-  * Solid enough to survive one disk fail (provided you monitor the RAID status and replace failed disks)
-RAID can be implemented in hardware or in software, using Linux RAID software implementation.
-I have been using the software RAID approach for more than two decades and i have never been let down:
-  * It's solid,
-  * it's simple,
-  * it works and it's efficient.
-  * Each disk can always be mounted as single drive, without the RAID array.
-If you choose to use a commercial external RAID solution, skip the RAID part ahead.
-I will assume you have two external drives called **/dev/sdb** and **/dev/sdc**. I will assume that **/dev/sda** it's the drive where Gentoo is installed.
-The size of the two disks is not important: get the biggest ones you can afford.
-I suggest, if you can afford them, to use SSDs because more silent and consume less power, which is a plus for a home server, but they are still more expensive than traditional drives.
-Any way, it doesn't matter whether you choose expensive high-end datacenter grade HDD or cheapo chinese dubious SSDs (well, i assume you factor in the value of losing your data ofc).
-A good approach to add more drives, when you run out of internal slots in your server, is to use USB-3/USB-C external drives. You can buy a JBOD box (Just a Bunch Of Disks) where you can store 2, 4 or even 8 or 16 disks sharing one USB plug. I have been using this type of setup for the best of the last 15 years without any data loss or corruption. Speedwise, you will be streaming your data over your home network, which more than often means WiFi. A good USB-3 SSD is more than capable to keep up any data transfer requirement for any streamed media today, even 4K, so there is not need to worry that external disks or USB-3 might be a bottleneck.
-Note: i will refer to //two// disks, but you can create more RAID arrays if you have //four// disks!
-===== Partitioning =====
-To create a software RAID, you need to first partition the two drives, for this job you can use the good old fdisk:
-<code bash>
- > su
- > fdisk /dev/sdb
-... do the partitioning ...
- > fdisk /dev/sdc
-... do the partitioning ...
-</code>
-You will need to be root for fdisk to work. You should be root at this point, tough. The //su// command might be redundant. How to use fdisk? I think you can find out easily. given that these should be new and clean disks, there is not much risk to mess up. Create a GPT partition table, for future-proof support, and one single partition filling up the disk, unless you want a more complex setup.
-Using //fdisk//, create one partition on each drive to fill it, that will be called **/dev/sdb1** and **/dev/sdc1**, these two partitions type needs to be of type //Linux RAID//. I assume the two drives are of the same size. If not, consider that the bigger one will have wasted space. In this case, create the partitions of identical sizes on both drives: the biggest drive will have free spare space that you can partition again as non-RAID partition.
-Save the changes and quit from fdisk, since the disks are not being used yet, you will not need to reboot the server.
-Remember that using Linux Software RAID you can create more than one partition and create more than one RAID-1 from two disks. For example, if you have a huge disk and want to separate two areas (one for data and one for webcam storage, for example) you can create **two** RAID-1 arrays by splitting both disks in two partitions each and mixing them up. Just don't create a RAID from two partitions on the **same** disk as that would be, at best, dumb.
-(if you need to retain your data and you have only two disks, you can create the RAID only on one of the two, which will be deleted, mount with only one drive, copy the data over from the other disk, then format the other disk and hot-add it to the RAID-1. How to do this in details it's not difficult to figure out, but be careful not to lose your data in the process)
-===== Creating the RAID array =====
-You need to create a new software RAID array out of **/dev/sdb1** and **/dev/sdc1**, for this you will use the //mdadm// command we have installed previously:
-<code bash>
- > mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sdb1 /dev/sdc1
-</code>
-since this is the first RAID array of the server (and probably the only one) it's called **/dev/md0**. If you have more than one RAID array, the naming will be different reflecting that.
-If you want to do the trick of copying existing data from one of the two disks, at this point you can create a RAID-1 array with only one drive by replacing the drive you do not want to add now with the work //missing//. You can then add at a later time the disk with the //--add// option of the //mdadm// tool.
-===== Format and mount =====
-You need to format and mount your newly created RAID array. You need to choose which filesystem you want to use. A common choice on Linux, and probably the more straightforward, is to go with EXT4. This might not be your best choice if you have SSDs or you want to leverage the error-correction and balancing of an advance filesystem like ZFS and BrtFS, but i like to go simple and so i will choose EXT4 for you here. I have been running my software RAID-1 on EXT-4 since it become stable well over a decade ago, and again i never lost any data to bugs or corruption.
-Now, i want to describe how i organize my services and data storage, because it's key in how to propery partition and secure your services (and data!).
-BLAH BLAH
-I will be assuming your media collection is located under **/data** and so you should run the following commands:
-<code bash>
- > mkfs.ext4 /dev/md0
- > mkdir /data
- > mount /dev/md0 /data
-</code>
-**/data** will be the entry point for your media collection, you will be creating some subfolders structure soon enough. You will also store all the temporary files and executable files for the various software stack that you will be using so that everything but the actual Gentoo installation will be on the RAID array. This will speed up any hardware failure or reinstallation you might need in the future and will also ensure that your main Gentoo partition will not get filled up by the various tools and the downloaded data.
-The newly formatted drive needs to be automatically mounted at every boot, so you need to add a line like this to **/etc/fstab**:
-<code>
-/dev/md0        /data     ext4            noatime         0 0
-</code>
-The //noatime// option will reduce USB traffic and wear-and-tear.
-===== Automate RAID at boot =====
-You also want to automate linux raid startup, so that upon reboot everything will still work just fine. To do so, the **mdraid** service needs to be started in the //boot// runlevel. Do NOT start it in the //default// runlevel or things will break badly after the first reboot.
-<code bash>
- > rc-update add mdraid boot
-</code>
-The //mdadm// service is not required, unless you want monitoring of your RAID array (nicluding email reporting) which is a **TODO**.
-You also want to ensure the **/dev/md0** device doesn't change name upon reboot (it happened when the USB drives change order on boot for example, or because you plug/unplug them), so put this line into your **/etc/mdadm.conf**:
-<code>
-ARRAY /dev/md0 UUID=1758bcfa:67af3a42:d3df2d83:ecbb0728
-</code>
-where the UUID can be read by the output of the command:
-<code bash>
- > mdadm -detail /dev/md0
-</code>
-===== Prepare the disk for the media collection =====
-You need to create the individual collections entry points like:
-<code bash>
- > mkdir /data/Films
- > mkdir /data/Tv
- > mkdir /data/Music
- > mkdir /data/Books
- > mkdir /data/Audiobooks
- > mkdir /data/daemons
- > mkdir /data/htdocs
-</code>
-The last two ones will not contain actual media, but will be used to store the installation (or the cache folders) for the various software described in this page and the root folder for the reverse-proxy.
-You will need do change the ownership of the folders, but you can do it after you have installed the *Arr's, since that step will also create the associated users. What you can do now is at least change the group ownership to the **media** group:
-<code bash>
- > chgrp media -R /data/*
-</code>

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