Re: [gentoo-user] NAS and replacing with larger drives
On 21/12/22 14:19, Frank Steinmetzger wrote: Am Wed, Dec 21, 2022 at 05:53:03AM + schrieb Wols Lists: On 21/12/2022 02:47, Dale wrote: ... In layman’s term, a stripe of mirrors. Raid-1 is the mirror, Raid-0 a (JBOD) pool. So mirror + pool = mirrorpool, hence the 1+0 → 10. ... I tend to use older drives that have led a hard life - so failure happens and I have to be prepared for it (by having good backups!) I have found mirrors to be problematic - sometimes when one drive fails, it causes a cascade of fails that includes the data on the mirror. With raid-10, its worse (even more fragile). When I eventually moved away from raid for my main data store it was because of a catastrophic failure of a bcache ssd fronting one of the mirrors causing all data to be lost - somewhat self-caused by using bcache to try and get some more speed out of the system, but as a RAID 10 with 4 HDD fronted by 4x SSD it should have survived ... In the end, I realised that raided data gave me a small speedup with little or no benefit as regards reliable data storage. I currently have one linux raid 10 using 4xSSD's that has suffered one SSD abrupt failure and survived - which I regard as "being lucky". SSD's are an issue as they usually fail abruptly without warning whereas spinning rust usually gives some warning. I've never tried RAID-6 as it was still considered buggy/risky at the time. No matter what storage system you use, offline backups are better - raid is NOT a viable backup. Fun, innit? YEP! BillK
Re: [gentoo-user] NAS and replacing with larger drives
Wols Lists wrote: > On 21/12/2022 02:47, Dale wrote: >> I think if I can hold out a little while, something really nice is going >> to come along. It seems there is a good bit of interest in having a >> Raspberry Pi NAS that gives really good performance. I'm talking a NAS >> that is about the same speed as a internal drive. Plus the ability to >> use RAID and such. I'd like to have a 6 bay with 6 drives setup in >> pairs for redundancy. I can't recall what number RAID that is. >> Basically, if one drive fails, another copy still exists. Of course, >> two independent NASs would be better in my opinion. Still, any of this >> is progress. > > That's called either Raid-10 (linux), or Raid-1+0 (elsewhere). Note > that 1+0 is often called 10, but linux-10 is slightly different. > > I'd personally be inclined to go for raid-6. That's 4 data drives, 2 > parity (so you could have an "any two" drive failure and still recover). > > A two-copy 10 or 1+0 is vulnerable to a two-drive failure. A > three-copy is vulnerable to a three-drive failure. > > In other words, a two-copy raid-10 might be taken out by a failure > that a raid-6 will survive. A three-copy raid-10 might be taken out by > a failure that will take out a raid-6. Choose your poison :-) > > Cheers, > Wol > > . > This is why at some point, I'd like to have two sets of backups. RAID or not. If I alternate between the two or update one weekly and the other monthly, odds of both being lost for some reason is slim. Nothing is ever impossible but not very likely. I could even keep the monthly backup, or second backup, in a outbuilding. That would protect from a house fire or something. I have a fire safe but still. I'm hoping that this Raspberry thing will work out. My reasons, I can upgrade easily, change OS and/or software if I want plus I may can even expand to a larger number of drives if needed. Buying a pre-built NAS, I think I'd be stuck with whatever I bought. Most likely no path for upgrade, changing OS and/or software or much of anything else either. Basically, it is what it is when I buy it. Given the info in the video you shared, I think something good is coming as soon as things get back to going again. Thanks again for the link. It lead to some other good videos too. Dale :-) :-)
Re: [gentoo-user] NAS and replacing with larger drives
Am Wed, Dec 21, 2022 at 05:53:03AM + schrieb Wols Lists: > On 21/12/2022 02:47, Dale wrote: > > I think if I can hold out a little while, something really nice is going > > to come along. It seems there is a good bit of interest in having a > > Raspberry Pi NAS that gives really good performance. I'm talking a NAS > > that is about the same speed as a internal drive. Plus the ability to > > use RAID and such. I'd like to have a 6 bay with 6 drives setup in > > pairs for redundancy. I can't recall what number RAID that is. > > Basically, if one drive fails, another copy still exists. Of course, > > two independent NASs would be better in my opinion. Still, any of this > > is progress. > > That's called either Raid-10 (linux), or Raid-1+0 (elsewhere). Note that 1+0 > is often called 10, but linux-10 is slightly different. In layman’s term, a stripe of mirrors. Raid-1 is the mirror, Raid-0 a (JBOD) pool. So mirror + pool = mirrorpool, hence the 1+0 → 10. > I'd personally be inclined to go for raid-6. That's 4 data drives, 2 parity > (so you could have an "any two" drive failure and still recover). > A two-copy 10 or 1+0 is vulnerable to a two-drive failure. A three-copy is > vulnerable to a three-drive failure. At first, I had only two drives in my 4-bay NAS, which were of course set up as a mirror. After a year, when it became full, I bought the second pair of drives and had long deliberations by then, what to choose. I went for raid-6 (or RaidZ2 in ZFS parlance). With only four disks, it has the same net capacity as a pair of mirrors, but at the advantage that *any* two drives may fail, not just two particular ones. A raid of mirrors has performance benefits over a parity raid, but who cares for a simple Gbit storage device. With increasing number of disks, a mirror setup is at a disadvantage with storage efficiency – it’s always 50 % or less, if you mirror over more than two disks. But with only four disks, that was irrelevant in my case. On the plus-side, each mirror can have a different physical disk size, so you can more easily mix’n’match what you got lying around, or do upgrades in smaller increments. If I wanted to increase my capacity, I’d have to replace *all* drives with bigger ones. With a mirror, only the drives in one of the mirrors need replacing. And the rebuild process would be quicker and less painful, as each drive will only be read once to rebuild its partner, and there is no parity calculation involved. In a RAID, each drive is replaced one by one, and each replacement requires a full read of all drives’ payload. With older drives, this is cause for some concern whether the disks may survive that. That’s why, with increasing disk capacities, raid-5 is said to be obsolete. Because if another drive fails during rebuild, you are officially screwed. Fun, innit? -- Grüße | Greetings | Salut | Qapla’ Please do not share anything from, with or about me on any social network. The boss is a human just like everyone else, he just doesn’t know. signature.asc Description: PGP signature
Re: [gentoo-user] NAS and replacing with larger drives
On 21/12/2022 02:47, Dale wrote: I think if I can hold out a little while, something really nice is going to come along. It seems there is a good bit of interest in having a Raspberry Pi NAS that gives really good performance. I'm talking a NAS that is about the same speed as a internal drive. Plus the ability to use RAID and such. I'd like to have a 6 bay with 6 drives setup in pairs for redundancy. I can't recall what number RAID that is. Basically, if one drive fails, another copy still exists. Of course, two independent NASs would be better in my opinion. Still, any of this is progress. That's called either Raid-10 (linux), or Raid-1+0 (elsewhere). Note that 1+0 is often called 10, but linux-10 is slightly different. I'd personally be inclined to go for raid-6. That's 4 data drives, 2 parity (so you could have an "any two" drive failure and still recover). A two-copy 10 or 1+0 is vulnerable to a two-drive failure. A three-copy is vulnerable to a three-drive failure. In other words, a two-copy raid-10 might be taken out by a failure that a raid-6 will survive. A three-copy raid-10 might be taken out by a failure that will take out a raid-6. Choose your poison :-) Cheers, Wol
Re: [gentoo-user] NAS and replacing with larger drives
Frank Steinmetzger wrote: > Am Thu, Dec 15, 2022 at 10:08:02PM -0600 schrieb Dale: > > I just read a news story about a new NAS model from Terramaster. > (Interestingly, they have their OS on an internal USB stick, so it’s easy to > swap it out for a standard Linux. And it uses a nice Celeron N5100 x86 > processor.) > >> Eventually, I plan to build a Raspberry Pi NAS. When I do, I'll post >> everything major I needed, boards, case etc for everyone to look at. >> I'll even try to upload some pics, or share as attachments if there is >> interest. Unless I find one heck of a deal on a used NAS that is. >> Still may build one even then. ;-) > In the comments section of the article, there was a link to this: > https://www.youtube.com/watch?v=R2S2RMNv7OU > A Raspberry Pi NAS with 1 Petabyte of storage. Enjoy. :) > I think if I can hold out a little while, something really nice is going to come along. It seems there is a good bit of interest in having a Raspberry Pi NAS that gives really good performance. I'm talking a NAS that is about the same speed as a internal drive. Plus the ability to use RAID and such. I'd like to have a 6 bay with 6 drives setup in pairs for redundancy. I can't recall what number RAID that is. Basically, if one drive fails, another copy still exists. Of course, two independent NASs would be better in my opinion. Still, any of this is progress. I've watched some videos by that guy but I don't recall seeing that one. That one, while pricey, shows that a lot can be done with a little Raspberry Pi. I read that a version 5 is coming, if they ever become available again. Right now, it seems the supply chain has grinded to a halt. It's hard to find quite a few things at the moment. Thanks for the link. I have a feeling even better is coming soon. Dale :-) :-) P. S. My backup I started days ago, maybe 1/4 to 1/3 of the way through. It's made it to the names starting with F. It has a ways to go. A lot of stuff starts with 'The'. That alone is quite large. It's making progress tho. Slowly. ;-)
Re: [gentoo-user] NAS and replacing with larger drives
Am Thu, Dec 15, 2022 at 10:08:02PM -0600 schrieb Dale: I just read a news story about a new NAS model from Terramaster. (Interestingly, they have their OS on an internal USB stick, so it’s easy to swap it out for a standard Linux. And it uses a nice Celeron N5100 x86 processor.) > Eventually, I plan to build a Raspberry Pi NAS. When I do, I'll post > everything major I needed, boards, case etc for everyone to look at. > I'll even try to upload some pics, or share as attachments if there is > interest. Unless I find one heck of a deal on a used NAS that is. > Still may build one even then. ;-) In the comments section of the article, there was a link to this: https://www.youtube.com/watch?v=R2S2RMNv7OU A Raspberry Pi NAS with 1 Petabyte of storage. Enjoy. :) -- Grüße | Greetings | Salut | Qapla’ Please do not share anything from, with or about me on any social network. Windows is great, you can download Linux with it. signature.asc Description: PGP signature
