231 lines
8.6 KiB
Markdown
231 lines
8.6 KiB
Markdown
+++
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title = 'test'
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hidden = true
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image = "https://i.extremetech.com/imagery/content-types/017c7K9UIE7N2VnHK8XqLds/images-5.jpg"
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+++
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<meta property="og:image" content="https://imgs.xkcd.com/comics/backup_batteries.png" />
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In short: 3-2-1 backup strategy + Disaster recovery plan.
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## Backup strategy
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You should have:
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- 3 copies of data
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- on 2 different types of storages
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- including 1 off-site copy
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AND you must test disaster recovery plan
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### Why so many copies?
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What if you accidently delete important files that you frequently edit? That's the reason to have snapshots.
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What if your main drive with data will die? That's the reason to have backup nearby.
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You think that you smart and have RAID for all those cases? Did you know that in drive arrays, one drive's failure significantly increases the short-term risk of a second drive failing. That's the reason to have off-site backup.
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What if your main storage Server will die with all drives in it due to power spike (flood,etc...)? So, do off-site backups.
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### 3 copies of data
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You should have:
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- Original data
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- 1 backup at place (another drive)
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- 1 backup in another place (encrypted in cloud, HDD stored in another remote location (friend's house))
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Backups which should be made regularly (daily or more frequently for critical data, +depends how "hot" data (how fast it changes)).
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My take on it - have a trusted source of data - RAID/Ceph and use snapshots to have copy of data to save some money on backup drives.
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### 2 types of storages
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You need to have different 2 types of storage to metigate if some error may affect all devices of 1 type.
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Storage types examples:
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- Internal HDD/SSD (we will focus on them)
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- External HDD (them)
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- USB drive/SSD
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- Tape library
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- Cloud storage (and them)
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### 1 off-site copy
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It's pretty simple:
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- encrypted cloud backup
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- encrypted HDD with backup in another town in friend's house (secured by bubble wrap)
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- or at least encrypted HDD in another house (also secured by bubble wrap)
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The more distant this off-site backup the better.
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## Disaster recovery plan
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People fall into 3 categories:
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- those who don't do backups yet
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- those who already do them
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- and those who do them and tested them
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You should be in 3rd catergory.
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__So what is disaster recovery plan?__
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You must be prepared in case if your main data and in-site backup dies. You must beforehand imitate:
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- accidental data removal (to test in-site snapshots)
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- drive failure and its change (to test RAID/Ceph solution)
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- main storage failure (to test restore from in-site backup)
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- entire site unavailability (to test off-site backup)
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Ideally you should write for yourself step-by-step guide what to do in any of those situations
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{{< spoiler Examples >}}
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## Examples
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### Enterprise-ish (Expensive at start, hard setup, easy to maintain)
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Ceph cluster:
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- requires 3 servers (at least) (OS - Proxmox)
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Ideally server motherboard, ECC RAM, Intel Xeon E5 v4 CPU Family or better / AMD Epyc analog
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- any number of drives (but at least 3 drives)
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Ideally enterpise-class (or with "RAID support"). The more IOPS - the better
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- [automatic snapshots](https://github.com/draga79/cephfs-snp)
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- 10Gb network (if you expect total 9-ish (or more) HDD drives or some SSDs)
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- Setup Samba/WebDAV/Nextcloud server which will share this storage to your network
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- and ideally SSD cache (at least 2 SSDs with PLP) (1tb each more than enough for 10TB of raw storage)
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Off-site backup:
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Cloud storage + [dublicati](https://github.com/duplicati/duplicati)
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OR
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Proxmoxx Backup Server at another city (e.g. at friend's house) with RAID1/5/6
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(thou you should set it up so if malware/hacker would get to root user it won't overwrite backups)
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#### Pros
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- Ideal if you already have homeserver and want to expand
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- Low chances of loosing data because you essentially have 3 copies (by default, 2 min) of data + hourly/daily/weekly/montly snapshots
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So if you get 2 dead drives in a same time - you still won't loose your data
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Essentially it covers 2 copies of data
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- If drive fails - you simple take it out, put new drive in and say that you want add this drive to pool via WebGUI
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- With SSD cache you can throw in any trashy HDD drives until they start to fail
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- You can add any number of drives
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- And if you need/want to be able to freely shutdown one of a servers and still be able to access data - you need to distribute drives so their raw storage would be even on each server.
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Or just add in few more server and distribute drives between them so you would still be able to access this storage
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- If you get your house+servers destroed - you wouldn't loose your data
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- You can access your storage from any device in your network as if it is on it device
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#### Cons
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- Expect 30% usable space from raw storage (you can use Erasure Coding (RAID5 analog) but it will be even slower)
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- Bad/Slow (in terms of IOPS and delay times) drives without PLP SSD cache can have amazingly bad total speed
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- Power usage might be a burden if you don't have any
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- More performance comes with more drives because speed = available IOPS and avarage access time for 2-3 drives that have that data. So more drives, more IOPS we have (excluding SSD cache case)
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- Ceph can be complicated to understand and maintain in case of failures
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### Home-server (Medium cost, medium difficulty, hard to maintain)
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CIFS/WebDAV/Nextcloud Share:
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- get any PC, install linux on it, setup Samba/WebDAV/Nextcloud share
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- X number of drives in RAIDZ (4+ even drives) (ideally RAIDZ2)
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- ZFS automatic Snapshots
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Off-site backup:
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Cloud storage + [dublicati](https://github.com/duplicati/duplicati)
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OR
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Regular (montly/weekly) manual encrypted backup to external HDD which is given to friend.
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#### Pros
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- It's relativly cheap
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- You get storage space from X-1 (or X-2) of drives
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- You can access your storage from any device in your network as if it is on it device
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- You can loose 1 (RAIDZ2 - 2) drive
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#### Cons
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- If drive fails - storage should be inaccessable for some time after you put new drive instead of failed drive.
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- If 2/3 drives fails in short perioud of time - you loose data
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- Hard to upgrade storage by using bigger disks, then more disks
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- Drives should have same size
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### Home PC (low cost, low difficulty, easy to maintain)
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We will just put 2 (or more) drives in RAID1 in your PC.
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Ideally - buy different drives with same-ish specs so they die in different time. And use file system with snapshot support
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Off-site backup:
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Cloud storage + [dublicati](https://github.com/duplicati/duplicati)
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OR
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Regular (montly/weekly) manual encrypted backup to external HDD which is given to friend.
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#### Pros
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- It's cheap
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- Setup easy to understand
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#### Cons
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- 50% space from raw storage
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- Potentially no snapshots if file system don't support it
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- All of the drives should die to loose data
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### Laptop (High cost, easy setup, easy to maintain)
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This time we will do opposite:
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- laptop with cloud storage synchronized in laptop and cloud (so files stored on laptop and cloud)
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- ideally file system snapshot support
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Off-site backup:
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Regular (montly/weekly) manual encrypted backup to external HDD which is given to friend.
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#### Pros
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- It's cheap at first, but costly in the long run
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- It's easy to setup and cloud providers give support (not the best but neverthless)
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- It's much easier to maintain since you don't have to deal with hardware
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#### Cons
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- It's the most privacy unfriendly setup because you will have unencrypted data in cloud - or way that will sync only encrypted data to cloud
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- Cloud subcription are costly in the long run
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- To have backup - you should be connected to internet
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- You may be affected by troubles by cloud provider
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### Laptop+PC (Low cost, easy setup, may be hard to maintain)
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We will use available hardware and its space, laptop+PC+off-site (friend's) PC for encrypted backups.
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The trick is - we will use [syncthing](https://github.com/syncthing/syncthing) - amazing tools, allows P2P sync storage.
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#### Pros
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- P2P, no other servers involved!
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- We can specify where data will be stored encrypted and where freely accessable
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- as easy to setup as cloud provider
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#### Cons
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- The issue may be if file edited in 2 places before sync = version conflict
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- Another problem - is storage space, it's easy to setup but it maybe hard to maintain if data drives have different free storage space.
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{{< /spoiler >}}
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{{< source >}}
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https://raidz-calculator.com/raidz-types-reference.aspx
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https://www.techtarget.com/searchdatabackup/definition/3-2-1-Backup-Strategy
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https://en.wikipedia.org/wiki/Hard_disk_drive
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{{< /source >}}
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