Alcor

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About Alcor

  • Birthday 01/13/1982

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  1. My understanding is that generally speaking - NAS drives are built with additional vibration dampening, sturdier construction and additional magnets for the RW armature to make it more stable/reliable. They are also designed for 24/7 workloads whereas typical desktop drives are expected (on average) to operate 8 hours a day. Perhaps that has something to do with it? I never power my gear down - it's always on. I can't really speak to the reliability (at least my experiences thereof) WRT NAS drives... the WD Red 3 TB I have is the first one I've used in a home-server environment. The rest have always been desktop-class drives.
  2. @trurl - I see! Okay, that makes sense... you're talking about the drive wear leveling tech in the firmware. So the physical cell the parity data gets written to could be reassigned internally by the drive based on wear-levelling patterns whereas, on a spinning mechanical disk, it knows exactly where on the platter it will be written to since the drive doesn't do any "wear leveling". Interesting! Okay - but then again, the sheer cost involved for some of us mere mortals would make it prohibitively expensive anyway. It'd be awesome from a performance standpoint though!
  3. Awesome! I'll give that a read! My use-case is primarily media streaming, and as a repository for backups. I work from home part of the time so I like to keep a backup on my server - internet bandwidth here is at a premium, so I can't use cloud storage solutions (due to bandwidth constraints). As a result, an on-prem solution is better for me. Out of curiosity, it deviates slightly from this thread, but is somewhat related in a way. I noticed Lime Tech specifically tell you not to use SSD's as primary storage/parity. Why is this? I mean common sense would tell me that it probably has to do with the fact that parity is probably very disk IO intensive, and you're likely to wear out the NAND on the SSD way more quickly than (for example) what a mechanical drive like a NAS drive is likely to die from. Is this it? Apart from that, it simply wouldn't be cost-effective to use SSDs purely from a capacity POV. They are still too expensive per GB compared to spinning disks.
  4. Whoops! LOL... My bad, I was copy/pasting... Correction... The next 3 disks after the first Parity are all Data drives :-) Basically, all of those with xfs filesystem. Thanks for the advice on what drives - The only non-NAS drive in there left is the ST3000DM001 drive - I read they apparently suffered from failures (that particular model). I actually replaced one of them - with the WD Red drive there. Does having a 2nd Parity drive make any difference? I've tried to get my head around how the 2nd parity drive actually works/what role it plays. My basic/high-level understanding of how it works is that you have enough redundancy to have 2 data drives fail on you, if you have/use a 2nd parity drive. Is there any performance benefit to the overall RW performance of the array or would you say it doesn't make much difference in a small array like mine?
  5. @bjp999 - Thanks for that! Really great information. So I think what you were speaking to about the full rotation of a disk before it can continue writing is what I was getting at. In other words, if I were to start retiring older drives in my array with newer ones - would it be better for me to try and stick to the same model of drive across my array (I know it doesn't really matter since unRAID was designed to use all makes/models of drives). Obviously factoring in the requirement that your data drives cannot exceed the capacity of your parity drive... I just want to make sure my array is optimised as best as possible. I'm not running an overly hardcore/big-scale system, it's more for home backup, media streaming and the like. Here are the specs of what I am currently running (rather modest). It is a repurposed old desktop machine that is now in service as a server since I replaced my daily driver... it is: AMD Phenom II X4 965 BE - Cooled with a Corsair Hydro h80i 16 GB DDR3 RAM (Dual Channel Mode) - non-ECC MSI 990FX-GD80 Motherboard (about 7 years old already but still running reliably) Parity Disk - Seagate 3TB ST3000VN000-1HJ166_W7304JLT Parity Disk - Seagate 3TB ST3000VN000-1HJ166_W7304JQ9 / xfs filesystem Parity Disk - Seagate 3TB ST3000DM001-1CH166_Z1F4C81K / xfs filesystem Parity Disk - WD Red 3TB WDC_WD30EFRX-68EUZN0_WD-WCC4N6NP6CYP / xfs filesystem Cache Disk 1 - Transcend 128GB TS128GSSD370S_D092260493 / btrfs Cache Disk 1 - Transcend 128GB TS128GSSD370S_D092260469 / btrfs
  6. I have 2 servers... 1. 16 GB (DDR3) - Primary 2. 8 GB (DDR3) - Secondary
  7. So first of all, I'm new here - so "Hi". Secondly, thanks to the unRAID team for an amazing OS! I did try to search for this but couldn't find anything immediately on the forums so thought I'd start this thread hoping to get some advice from the community. Currently, I have a mixed array of disks on my primary unRAID server made up of various rotational speeds, caches, manufacturers etc. What I wanted to know is, I am starting to approach a point where I will soon need to start investing in newer, higher capacity drives to expand my storage. So, my question/what I'm looking to find out is this: Is there a recommended method of provisioning drives in an unRAID server to optimize the performance of the system? In other words, I'm trying to work out things like: * Should one try to provision the same model drives in the array? * How much does the onboard drive cache matter in an array? * Is performance impacted if drives vary in their cache amounts? * Does the rotational speed of the drives matter? * Should the parity disk be a higher performance drive compared to the storage drives in the array? Reason I'm asking is because I have noticed that in some cases, a copy operation to my server often will hit speeds of just over 100 MB/s from a networked machine, but then if it's a particularly large copy, at some point it starts slowing down to a crawl at times even appearing to pause before resuming. Monitoring disk activity it would seem that the parity drive appears to be grinding hard to write parity, while the storage drives in the array often appear to be waiting for the parity disk to catch up. It got me wondering about the relationship between the disk performance of the parity drive vs. the storage drives, and as the number of storage drives increase, how that has an impact on overall array performance if there is only 1 parity drive. Any advice is welcome! Thanks!