NAS disk compatibility question
Discussion
I have a synology NAS, it's just alerted me that one of my disks has failed.
I currently have a 3tb WD and a 3tb Seagate in a RAID array.
Looking at the synology compatibility chart it lists various models, for example from seagate:
St3000n007 - 2ah16m
St3000n007 - 2e4166.
When looking for a replacement disk usually the last part of the model number isn't listed.
So my question is, does this matter? Will any St3000n007 disk work?
I currently have a 3tb WD and a 3tb Seagate in a RAID array.
Looking at the synology compatibility chart it lists various models, for example from seagate:
St3000n007 - 2ah16m
St3000n007 - 2e4166.
When looking for a replacement disk usually the last part of the model number isn't listed.
So my question is, does this matter? Will any St3000n007 disk work?
I don’t have much faith in the disk health reporting by DSM.
If you have a RAID configuration I would try repairing the storage pool first by clicking repair of the failed disk before buying a replacement. This is what I did a couple of months back when it reported a second failed disk after replacement and the storage pool has been healthy since with no random disk errors being reported.
If you have a RAID configuration I would try repairing the storage pool first by clicking repair of the failed disk before buying a replacement. This is what I did a couple of months back when it reported a second failed disk after replacement and the storage pool has been healthy since with no random disk errors being reported.
Somebody said:
I don’t have much faith in the disk health reporting by DSM.
If you have a RAID configuration I would try repairing the storage pool first by clicking repair of the failed disk before buying a replacement. This is what I did a couple of months back when it reported a second failed disk after replacement and the storage pool has been healthy since with no random disk errors being reported.
seconded. DSM marked my Array as healthy, and disk 2 as healthy with some bad sectors. I ran the various reports and maintenance.If you have a RAID configuration I would try repairing the storage pool first by clicking repair of the failed disk before buying a replacement. This is what I did a couple of months back when it reported a second failed disk after replacement and the storage pool has been healthy since with no random disk errors being reported.
It however was NOT healthy, it was busy trying to fix errors it was not telling me about, so busy my Virtual machine was failing to run (Home Assistant) and taking 10 minutes to restart, if at all.
I replaced the "healthy" drive 2 and all was good again.
OP - I ignored the Synology approved list - much like I ignore manufacturer tyre brands, However, my mistake was ignoring the fact (that I was not aware of) that RAID/NAS optimised drives are set to discard bad sectors quickly rather than try and fix them for ever and a day, which is what I believe was bringing my NAS to its knees.
I bougth an identical used disk for now, all is good, but when they are cheap enough I'll replace them with NAS optimised drives - though I won't be looking at any "compatibility" list from Synology.
You currently run two different disks, which is apparently a sin all ni itself.
Watcher of the skies said:
So my question is, does this matter? Will any St3000n007 disk work?
Fundamentally, yes. You can also run "unsupported" drives in the units.But this is important.
bangerhoarder said:
Not bought one for a couple of years, but the most important thing last time I did was to avoid any disks that are SMR, rather than CMR. I sent one SMR drive back when I tested it and it brought everything else in the array down to its crummy level.
The main difference between CMR (Conventional Magnetic Recording) and SHR (Shingled Helium Recording) drives lies in the way data is written to and organized on the hard drive's disk platters. Here's a breakdown:CMR (Conventional Magnetic Recording) Drives:
1. Writing Method:
- In CMR drives, data is written in individual, non-overlapping tracks.
- This allows for more flexibility in random read and write operations.
2. Performance:
- CMR drives perform better in workloads involving random writes, as the non-overlapping tracks make it easier to write data to any part of the disk without affecting adjacent tracks.
3. Use Cases:
- These drives are often used in general-purpose desktop and server environments, as well as for applications that involve frequent random access to data.
4. Data Integrity:
- CMR drives are more robust in terms of data integrity during random writes. The ability to write to individual tracks reduces the chance of data corruption.
SHR (Shingled Helium Recording) Drives:
1. Writing Method:
- SHR drives use a shingling technique where data is written in overlapping tracks, similar to how shingles are placed on a roof.
- The "shingled" nature of these tracks means that writing to a new track can overwrite parts of adjacent tracks, which can limit random write operations.
2. Performance:
- SHR drives tend to perform slower than CMR drives when it comes to random writes because of the overlapping tracks, which make modifying data more complicated.
- They are typically optimized for sequential write operations, such as video storage or archival use, where data is written in large, continuous blocks.
3. Use Cases:
- SHR drives are more commonly used in high-capacity applications such as storage for media archives, surveillance video, or other environments where large amounts of data are written sequentially.
4. Data Integrity:
- Due to the overlapping tracks, there is a higher risk of data loss or corruption during random writes unless data management strategies like caching are used.
Key Differences Summary:
- CMR is better for environments where random write performance and data integrity are crucial.
- SHR is optimized for environments with large sequential writes and higher storage capacity needs but can suffer from slower random write performance due to the shingled track structure.
In short, CMR is ideal for general-purpose usage and workloads requiring frequent random writes, while SHR is designed for bulk storage needs, especially for sequential data writes.
For NAS (Network-Attached Storage) workloads, the choice between CMR and SHR drives depends on the specific usage scenario, but in general:
CMR (Conventional Magnetic Recording) Drives:
- Better suited for NAS workloads that involve frequent random read and write operations. This includes:
- File sharing and access by multiple users or devices.
- Running applications directly from the NAS (such as databases or virtual machines).
- Mixed workloads with frequent small write operations (e.g., document editing, media libraries with lots of metadata updates).
- Advantages for NAS:
- More consistent performance for random writes, which is crucial for a NAS serving a variety of file types and applications.
- Better for setups where data integrity during random writes is important.
- Typical Use Case:
- NAS used for general-purpose file storage, collaborative work environments, or any application that requires balanced read/write access.
SHR (Shingled Helium Recording) Drives:
- Better suited for NAS workloads that focus on large, sequential write operations with relatively infrequent random writes. This includes:
- Surveillance systems (where large video files are continuously written).
- Archival storage or cold storage (large amounts of data written once, accessed infrequently).
- Backup solutions with large files, such as disk-to-disk backups.
- Advantages for NAS:
- Higher storage capacities at a lower cost, which makes them ideal for systems that need to store massive amounts of data but aren't heavily dependent on random write performance.
- Optimized for sequential workloads, where the data is written in large chunks rather than constantly modified.
- Typical Use Case:
- NAS used for media archiving, surveillance storage, or any situation where data is mostly written once and accessed later without constant updates.
Which One is More Suited for NAS?
- CMR drives are typically more suited for general-purpose NAS workloads due to their better random write performance and more predictable behaviour.
- SHR drives are more suitable for high-capacity storage needs in NAS setups where sequential writes are the primary workload (e.g., video surveillance or archival storage).
In conclusion:
- If your NAS will be used for general file sharing, active access by multiple users, or running applications, CMR drives are the better choice.
- If your NAS is mainly for storing large files with less frequent updates (like backups or video storage), SHR drives could be a more cost-effective solution.
eeLee said:
2. Performance:
- SHR drives tend to perform slower than CMR drives when it comes to random writes because of the overlapping tracks, which make modifying data more complicated.
- They are typically optimized for sequential write operations, such as video storage or archival use, where data is written in large, continuous blocks.
Not sure if you wrote that or it's AI, but most (all?) SMR drives use a small CMR area as a buffer. So you can write (for example) 2GB of data at normal speed (150MB or whatever). Then later when the drive is idle it will go and write the contents of that buffer to the real SMR storage area of the drive in the background so in 'normal use' you don't notice the slow write performance of the SMR area.- SHR drives tend to perform slower than CMR drives when it comes to random writes because of the overlapping tracks, which make modifying data more complicated.
- They are typically optimized for sequential write operations, such as video storage or archival use, where data is written in large, continuous blocks.
The real issue for SMR drives in a NAS though, is that during a large file copy (or even worse, a RAID rebuild) when the drive fills the small CMR area and needs to write directly to the SMR area. They are *extremely* slow for this.
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