Synology one bad sector crashes whole volume RAID0
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@donahue said in Synology one bad sector crashes whole volume RAID0:
Is there some sort of jbod mode or something that is common for wanting a larger drive, giving up the performance of R0? Then, when a drive does fail, it only takes out that drive and not the whole shebang? Is that actually a thing in production use?
RAID 0 should, like JBOD setups, really just be for ephemeral data, like caches.
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@scottalanmiller said in Synology one bad sector crashes whole volume RAID0:
@donahue said in Synology one bad sector crashes whole volume RAID0:
Is there some sort of jbod mode or something that is common for wanting a larger drive, giving up the performance of R0? Then, when a drive does fail, it only takes out that drive and not the whole shebang? Is that actually a thing in production use?
RAID 0 should, like JBOD setups, really just be for ephemeral data, like caches.
that's not an answer to his question.
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@dashrender said in Synology one bad sector crashes whole volume RAID0:
@scottalanmiller said in Synology one bad sector crashes whole volume RAID0:
@donahue said in Synology one bad sector crashes whole volume RAID0:
Is there some sort of jbod mode or something that is common for wanting a larger drive, giving up the performance of R0? Then, when a drive does fail, it only takes out that drive and not the whole shebang? Is that actually a thing in production use?
RAID 0 should, like JBOD setups, really just be for ephemeral data, like caches.
that's not an answer to his question.
It's the answer he needs, not the answer he wants.
Individual drives are just "smaller RAID 0s", if you have to worry about the size of the failure domain, it means you can't implement the solution in production.
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@guyinpv said in Synology one bad sector crashes whole volume RAID0:
Interestingly, I force turned off the Synology, pulled the drives and did a quick canned air cleanup.
Turned back on and it came to life. Looking at the drive screen, the count of bad sectors is now at 38.
This makes no sense, jumping from 0 bad to 38 out of the blue.I know enough about drives to know they can recover from bad sectors and avoid those areas of the disk. It's weird to me that it would bring down the entire volume and crash the whole thing over a bad sector.
It's gonna fail again. No it's not, it's RAID 0, it needs EVERY sector. Think of it as a password, lost one character, you lost the entire password.
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@guyinpv said in Synology one bad sector crashes whole volume RAID0:
The NAS has 2 x 4TB WD Red drives. I'm running them striped since I wanted more space and perhaps speed.
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SATA drives speed > 1 Gbps, there was no speed advantage. Since you didn't need the space, all you did was add risk by running RAID 0.
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@harry-lui said in Synology one bad sector crashes whole volume RAID0:
@guyinpv said in Synology one bad sector crashes whole volume RAID0:
The NAS has 2 x 4TB WD Red drives. I'm running them striped since I wanted more space and perhaps speed.
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SATA drives speed > 1 Gbps, there was no speed advantage. Since you didn't need the space, all you did was add risk by running RAID 0.
Yes it was risk. The NAS was originally just going to be an external backup for the server. I only used RAID 0 for the combined space which is close to the what my server has which uses RAID 10 and 4 drives.
Frankly I just thought it would be more robust. I mean, I know it "can" fail, just didn't think it would be within a year. I also know my car tires can get blowouts, but I don't expect one every month or two either.
I'll probably replace this WD Red now it's at 39 bad sectors. Redo the RAID with a mirror instead. I'll lose the space but I don't expect to use up 4TB soon anyway.
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Aren't we discussing something like 7TB usable space? Why is this even a question. Four 8TB drives would give you 8TB usable in a RAID1.
There is zero benefit listed with what has been described so far with regards to RAID0.
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@guyinpv said in Synology one bad sector crashes whole volume RAID0:
Frankly I just thought it would be more robust. I mean, I know it "can" fail, just didn't think it would be within a year. I also know my car tires can get blowouts, but I don't expect one every month or two either.
Statistically, you'd expect it to be around a year. RAID 0 is incredibly unstable because it takes the risk of a single drive and magnifies it dramatically. So if the average failure of a single drive is, maybe, once every six years, RAID 0 with four drives would make that every 1.5 years on average. And that's just an average. So well inside the bell curve are failures at six months and three years.
And RAID 0 has failures that cause all data loss that don't cause full data loss on single drives. The RAIDing process making RAID 0 astronomically more dangerous than just 4x the risk of a lone drive.
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Ah so you actually have two disks with 4TB each and went with the "I need more space" RAID0.
The fix here is bigger disks and RAID1 in that case, it's going to be slow (being 5400 RPM) but at least you have the protection you were looking for.
Granted this is backup only.
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@dustinb3403 said in Synology one bad sector crashes whole volume RAID0:
Ah so you actually have two disks with 4TB each and went with the "I need more space" RAID0.
The fix here is bigger disks and RAID1 in that case, it's going to be slow (being 5400 RPM) but at least you have the protection you were looking for.
Granted this is backup only.
I'm guessing he didn't buy the drives, but already had them.
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@scottalanmiller That doesn't matter in terms of the discussion. If backup space is a priority and you can't make it work with the equipment you have you need to purchase more space.
RAID0 is a non-production setup in most cases like was discussed above. For backups, yeah okay maybe you can skate by. But why risk it if this is the only backup's you might have?
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@scottalanmiller said in Synology one bad sector crashes whole volume RAID0:
@dustinb3403 said in Synology one bad sector crashes whole volume RAID0:
Ah so you actually have two disks with 4TB each and went with the "I need more space" RAID0.
The fix here is bigger disks and RAID1 in that case, it's going to be slow (being 5400 RPM) but at least you have the protection you were looking for.
Granted this is backup only.
I'm guessing he didn't buy the drives, but already had them.
I did buy them new, but the Synology case itself was expensive too. WD REDs at 4TB * 2 just hit the budget. The whole thing was like $800+.
I can get buy with RAID1 and 4TB drives for a while. As a backup, I might not get 5 full backup sets or whatever but it will do with some incrementals.
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how critical are those backups? If you needed them and lost them, do you lose more than $800?
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@guyinpv said in Synology one bad sector crashes whole volume RAID0:
@scottalanmiller said in Synology one bad sector crashes whole volume RAID0:
@dustinb3403 said in Synology one bad sector crashes whole volume RAID0:
Ah so you actually have two disks with 4TB each and went with the "I need more space" RAID0.
The fix here is bigger disks and RAID1 in that case, it's going to be slow (being 5400 RPM) but at least you have the protection you were looking for.
Granted this is backup only.
I'm guessing he didn't buy the drives, but already had them.
I did buy them new, but the Synology case itself was expensive too. WD REDs at 4TB * 2 just hit the budget. The whole thing was like $800+.
I can get buy with RAID1 and 4TB drives for a while. As a backup, I might not get 5 full backup sets or whatever but it will do with some incrementals.
One full on RAID 1 is better than a hundred on RAID 0.
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the cost of 2x4tb is basically the same as a single 8tb if we are talking WD red's. One drive at 8TB would be safer than 2x4tb in raid 0. You could always add the second drive and make it raid 1 later.
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Do you have a backup or do you need the data?
I do data recovery.
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Yeah the drives are ~$125 vs ~$260. I'd go with less backups and RAID1 over RAID0.
I have to ask why is there an $800 limit on this system if you know how many backups you need? Especially if you're forced to use RAID0 to meet the requirement of "5 full backup sets". That would seem to say "I need this much protection, what do I need to spend to get that protection in a reasonable way?"
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@dustinb3403 said in Synology one bad sector crashes whole volume RAID0:
I have to ask why is there an $800 limit on this system if you know how many backups you need?
In theory, this budget is either based off of the perceived value of the data and/or it defines their value of their data.
The "rule of thumb" for figuring this out is that you would spend around a quarter of the data value at max for protection. So if this was the sole protection, they'd see their data (that is specifically affected by this device) as having a value of no more than $3,200. Which is reasonable, it might be rather unimportant data that's just nice to not have to recreate.
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@scottalanmiller In that scenario then you'd still have to meet the following point I mentioned just above.
What do I need to spend to protect me from a $3,200 loss? It's clearly more than the money that was spent already, I'd say by about $300.
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@donahue said in Synology one bad sector crashes whole volume RAID0:
how critical are those backups? If you needed them and lost them, do you lose more than $800?
Not that critical, at least not now. Once I start internally hosting some important data records and DBs and other LAN stuff, it will be.
@donahue said in Synology one bad sector crashes whole volume RAID0:
the cost of 2x4tb is basically the same as a single 8tb if we are talking WD red's. One drive at 8TB would be safer than 2x4tb in raid 0. You could always add the second drive and make it raid 1 later.
A year ago or more the prices were higher, not even sure there were 8TB drives at all? I think the 2TB drives were around $200 each, and the Synolgy about $400, so it was $800+ fully configured.
@ccwtech said in Synology one bad sector crashes whole volume RAID0:
Do you have a backup or do you need the data?
I do data recovery.
Thanks man, but oddly, just turning the Synology off and on again brought the stripe back to life and worked just fine until next sector was discovered bad.
@scottalanmiller said in Synology one bad sector crashes whole volume RAID0:
@dustinb3403 said in Synology one bad sector crashes whole volume RAID0:
I have to ask why is there an $800 limit on this system if you know how many backups you need?
In theory, this budget is either based off of the perceived value of the data and/or it defines their value of their data.
The "rule of thumb" for figuring this out is that you would spend around a quarter of the data value at max for protection. So if this was the sole protection, they'd see their data (that is specifically affected by this device) as having a value of no more than $3,200. Which is reasonable, it might be rather unimportant data that's just nice to not have to recreate.
I don't know how to put a price on data. I mean, let's say we lost our pile of vendor invoices. Well maybe there are 150 of these files. So if those were lost, we'd have to spend employee time tracking down all our outstanding orders, recreate the files, then track down all our own customer orders waiting on those products. So I don't know, that's maybe 4 people working for 3 days or so to figure that out. So let's say around $2000 of labor time. Plus if they are doing this work, then they aren't doing other sorts of work that may or may not translate to revenue, so maybe add $1000 for lost revenue perhaps?
This is all very speculative. Some data maybe can't be recovered at all, perhaps old reports or records.
Anyway, I didn't say $800 was the budget limit, I'm just saying that's what I spent at the time. My original plan was to push ALL my workstation backups to the NAS, which would have surpassed a RAID1 4TB mirror. Hence the stripe originally. Plus acting as backup for the server which wasn't holding anything important, I was just going to store some snapshots of the VMs.
All that to say, I never ended up putting workstation backups on it, and it became more of a general purpose network sharing NAS, and so I'm only using about 1.2TB.
You can imagine, since the NAS become general purpose, it wasn't classified as a backup device any more, but a primary device! So now it needed backed up as well. I bought a 4TB USB drive and that's when I tried to backup the NAS to the USB and it started failing and all this went down.
Here is the odd part, ONLY when the Hyper Backup tool does a backup does it start finding bad sectors. But if I use a tool like Robocopy and just copy all the files manually, no failures. What gives?
