5 ms·

> * It won't boot on a degraded array by default, requiring manual action to mount it That by itself is a complete deal breaker.

by klysm 4y ago

chomp 4y ago
Why? Are you in a position where you can’t modify grub or fstab?
- dale_glass 4y ago
  Because RAID is a High Availability technology. It's not a backup. It doesn't protect against mistakes, bugs, or the server failing in some other way. What it's good for is for ensuring that work keeps happening if a disk fails. And disk failures happen to be fairly frequent, since spinning rust is a rather delicate technology. If somebody has to connect to the machine and fiddle with it by hand it means that the system has been down, possibly for hours, when that was the exact thing you were trying to prevent by setting up RAID on it.
  - viraptor 4y ago
    You don't have to modify it after a failure. You can set it right now to explicitly say "when I end up in a degraded state, I want to boot anyway". > What it's good for is for ensuring that work keeps happening if a disk fails. Different services have different priorities. I want my work servers to keep running, but my home server under the desk to stop until I replace the failed drive. Btrfs gives you a choice.
- alerighi 4y ago
  No, because I want to be elsewhere on a Sunday evening than in front of a computer modifying fstab to bring a production server back online.
  - RealStickman_ 4y ago
    Unless you want to reboot the server this shouldn't affect you in any way.
    - ndsipa_pomu 4y ago
      Unless you get a power outage or some other event that causes a reboot (e.g. STONITH)
josephcsible 4y ago
IMO, the inconvenience this causes is outweighed by the prevention of data loss for people who otherwise would never have noticed the degraded array.
- ClumsyPilot 4y ago
  I think this is the difference in target audience - for home use, maybe I won't have monitoring, so it should fail to boot. For enterprise, if you dont have monitoring setup it's on you
- ilyt 4y ago
  Right but if it's remote server you're fucked and you can't login on it to even assess what happened
  - kiririn 4y ago
    That’s what the likes of dropbear-initramfs is for
  - josephcsible 4y ago
    Don't servers tend to include some kind of out-of-band management like HP iLO, Dell iDRAC, or OpenBMC?
  - ndsipa_pomu 4y ago
    This is why I want servers to always boot to an OS whenever possible. It's fine if production data is not available until someone fixes an array, but without the OS, it's a pain to even figure out what's happened, let alone fix it.
cycomanic 4y ago
Hold on, people make this out to be like if a disk fails it requires immediate intervention. However if the system already booted it stays up. Who reboots a production system without monitoring it? Also if you boot with a degraded disk are you not asking for massive trouble, because if another disk fails you might end up with data loss which is IMO much worse on a production system than not being able to boot until you add another disk.
- justsomehnguy 4y ago
  > Who reboots a production system without monitoring it? Anyone. > Also if you boot with a degraded disk are you not asking for massive trouble > not being able to boot until you add another disk Great. I'm just a [sys]admin who were given a task to do something on $server. I jump around the red tape, claw out a 15 minute downtime because the task requires reboot, proceed with all that corporate dance with notification emails. I do my thing, reboot the server and it doesn't return back online. Suddenly I broke the server, missed maintenance window, amount of mails with CC and RE: in my mailbox grows in geometric progression and the most important - now I need to find out who were responsible for the server, contact him and [kick his ass] ask him to diagnose what is going on. Bonus points if: server doesn't have a meaningful BMC/iLO/iDRAC with KVM console it does have it but it's broken for some reason eg requires Java 6 on Vista server was configured 10 years ago by a greybeard who is not only retired but already died from the old age server is 6000km away from any place with a replacement disks and the earliest time when you can send the replacement would be the next spring when the ice would break and taw enough for the ships to move. Of course you can hire a helo to deliver it, which get your ass chewed for an unplanned $50k expenses Also: https://news.ycombinator.com/item?id=33963000 https://news.ycombinator.com/item?id=33963000
  - wtallis 4y ago
    It sounds like you're hypothesizing a long chain of bad decisions, and then ridiculing btrfs for taking the choice that means your next bad decision only culminates in (predictable, preventable) downtime rather than data loss.
happymellon 4y ago
Unless you give it permission. It's an option to enable. If you needing to configure something is a dealbreaker then having RAID is probably not for you anyway.

> * It won't boot on a degraded array by default, requiring manual action to mount it That by itself is a complete deal breaker.

by klysm 4y ago

> * It won't boot on a degraded array by default, requiring manual action to mount it That by itself is a complete deal breaker.

chomp 4y ago

Why? Are you in a position where you can’t modify grub or fstab?

dale_glass 4y ago
Because RAID is a High Availability technology. It's not a backup. It doesn't protect against mistakes, bugs, or the server failing in some other way. What it's good for is for ensuring that work keeps happening if a disk fails. And disk failures happen to be fairly frequent, since spinning rust is a rather delicate technology. If somebody has to connect to the machine and fiddle with it by hand it means that the system has been down, possibly for hours, when that was the exact thing you were trying to prevent by setting up RAID on it.
- viraptor 4y ago
  You don't have to modify it after a failure. You can set it right now to explicitly say "when I end up in a degraded state, I want to boot anyway". > What it's good for is for ensuring that work keeps happening if a disk fails. Different services have different priorities. I want my work servers to keep running, but my home server under the desk to stop until I replace the failed drive. Btrfs gives you a choice.
alerighi 4y ago
No, because I want to be elsewhere on a Sunday evening than in front of a computer modifying fstab to bring a production server back online.
- RealStickman_ 4y ago
  Unless you want to reboot the server this shouldn't affect you in any way.
  - ndsipa_pomu 4y ago
    Unless you get a power outage or some other event that causes a reboot (e.g. STONITH)

josephcsible 4y ago

IMO, the inconvenience this causes is outweighed by the prevention of data loss for people who otherwise would never have noticed the degraded array.

ClumsyPilot 4y ago
I think this is the difference in target audience - for home use, maybe I won't have monitoring, so it should fail to boot. For enterprise, if you dont have monitoring setup it's on you
ilyt 4y ago
Right but if it's remote server you're fucked and you can't login on it to even assess what happened
- kiririn 4y ago
  That’s what the likes of dropbear-initramfs is for
- josephcsible 4y ago
  Don't servers tend to include some kind of out-of-band management like HP iLO, Dell iDRAC, or OpenBMC?
- ndsipa_pomu 4y ago
  This is why I want servers to always boot to an OS whenever possible. It's fine if production data is not available until someone fixes an array, but without the OS, it's a pain to even figure out what's happened, let alone fix it.

cycomanic 4y ago

Hold on, people make this out to be like if a disk fails it requires immediate intervention. However if the system already booted it stays up. Who reboots a production system without monitoring it? Also if you boot with a degraded disk are you not asking for massive trouble, because if another disk fails you might end up with data loss which is IMO much worse on a production system than not being able to boot until you add another disk.

justsomehnguy 4y ago
> Who reboots a production system without monitoring it? Anyone. > Also if you boot with a degraded disk are you not asking for massive trouble > not being able to boot until you add another disk Great. I'm just a [sys]admin who were given a task to do something on $server. I jump around the red tape, claw out a 15 minute downtime because the task requires reboot, proceed with all that corporate dance with notification emails. I do my thing, reboot the server and it doesn't return back online. Suddenly I broke the server, missed maintenance window, amount of mails with CC and RE: in my mailbox grows in geometric progression and the most important - now I need to find out who were responsible for the server, contact him and [kick his ass] ask him to diagnose what is going on. Bonus points if: server doesn't have a meaningful BMC/iLO/iDRAC with KVM console it does have it but it's broken for some reason eg requires Java 6 on Vista server was configured 10 years ago by a greybeard who is not only retired but already died from the old age server is 6000km away from any place with a replacement disks and the earliest time when you can send the replacement would be the next spring when the ice would break and taw enough for the ships to move. Of course you can hire a helo to deliver it, which get your ass chewed for an unplanned $50k expenses Also: https://news.ycombinator.com/item?id=33963000 https://news.ycombinator.com/item?id=33963000
- wtallis 4y ago
  It sounds like you're hypothesizing a long chain of bad decisions, and then ridiculing btrfs for taking the choice that means your next bad decision only culminates in (predictable, preventable) downtime rather than data loss.

happymellon 4y ago

Unless you give it permission. It's an option to enable. If you needing to configure something is a dealbreaker then having RAID is probably not for you anyway.