One aspect of my job is designing and building large-scale storage systems (often known as "SANs", or "Storage Area Networks"). Typically, we use a tiered approach with SSD's and HDD's combined.
That said, each one has specific benefits.
SSD's almost always have a higher Cost-per-Byte. I can get 10k SAS 4kn HDD's with a cost-per-gigabyte of $0.068/GB USD. ...
HDD is still quite preferred
Is it? I'm not sure it is to be honest.
HDD's come in large sizes for a decent price right now, that's undeniable, and I think people trust them for longer data retention than SSDs too. Also when SSDs die they tend to die completely, all in one go, whereas HDDs tend to die in a more predictable way that maybe allows more time ...
Solid state for everything hot: interactive use, databases, anything online. Spindles as cheap warm storage, only for not-quite-cold archives or infrequently accessed data. In particular, HDDs in a staging area before backups are archived to tape.
Different media types for hot versus cold also helps with some diversity. A data loss flaw in a brand of SSD ...
The big advantage of an SSD is speed and reliability however, one of the dirty little secrets is the limited number of write cycles that an SSD has. If you are building a server that has a lot of hard drive write activity like a database or email server you will need a more expensive SSD that has higher endurance.
NAND Flash has 3 types
Use tape for long-term archives and multiple public clouds (multiple tape-in-cloud still as no way anybody can store PBs of "ice cold" data on anything except tape). Hard disk isn't designed to store data for a long periods of time. 3-2-1 backup rule is in power either way.
HDD is still quite preferred, but why?
That depends on who you talk to, their background (management, IT, sales, etc), and what type of server the discussion is in reference to. HDDs are generally an order of magnitude less expensive per byte, but use more power and are almost always slower, workload dependent.
Almost always it comes down to cost and how ...
Bad news - your harddrive is NOT comparitively healty. Well, it is more healthy compared to completely dead drive, but it is damaged. Both the Linux kernel messages and S.M.A.R.T. logs confirm errors reading certain areas of the disk:
ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE
1 Raw_Read_Error_Rate ...
As already mentioned, the big difference is price per GB vs random IO performance.
Take, for example, a Seagate Exos 16 TB: at ~550$, it commands 0,034$/GB. Now compare it with with an entry-level (speed wise) Micron 5200 ECO 7.68 TB priced at ~1300$, with a resulting 0,14$/GB ratio: the HDD is 5x cheaper, while being 2x bigger also. On the other side, SSD ...
The two main factors to consider are:
Performance (in access time and throughput)
Cost per gigabyte
SSDs blow HDDs out of the water in terms of performance. If you need high throughput and low access times, nothing beats SSDs.
But the cost per gigabyte of SSDs is much higher than that of HDDs. If you need a lot of storage and throughput or access times ...
I have yet to see an SSD dying because of the write load (they are supposed to become readonly in this case). Not that they don't die for other reasons - including, but not limited to overheating and firmware bugs.
And I have seen a dead HDD. A lot more of them, actually.
So much about the reliability.
In some cases it makes sense to make mixed ...
Well it seems that v0.11 (which is all you get from Ubuntu 16.04 repos) doesn't have that functionality. Ubuntu 18.04 repos contain v0.15 (still not recent) but there you do get the functionality. No PPA available. Plenty of instructions to manually install newer versions or you can use my Ansible role:
- name: Download package
It looks like your system is trying to activate swap on a device partition /dev/sdj2, which is not present. Check /etc/fstab to see what swap partitions have been defined, and make any necessary corrections. Once this file is fixed, run systemctl daemon-reload to cause systemd to re-read it.