a few quick questions about NAS (QNAP vs. Synology, and other)

[mando2023]

hi all,
I am considering buying a NAS solution. All I have right now is a stack of external 2, 4, and 5 TB external drives that I have to connect a few at a time and I would really like to have all content available all the time.
Additionally I guess the NAS is supposedly a more secure solution in terms of back up.

I have never used NAS before, so please indulge ...

I am looking at Synology 6 Bay 2.5" NAS DS620slim (Diskless) available at $675 CAD.
Q1: Is Synology really a better choice than QNAP?
Q2: Is there a limit to the total size of the hard drives that go in each slot? I have not seen anything in the specs about this.
Q3: Is it possible to fill in only, say 3 bays out of six for now and add drives later?
Q4: DO all drives need to have the same specs/size ?
Q5: What is the lowest form of stripping and what is the ratio of useful vs. total space used? (with my limited knowledge I would say that a mirror would take 2 times the size mirrored, therefore, the ratio would be 0.5)

Thank you very much,
mando2023

 

[sfx2000]

While NAS is a nice place to centralize backups, do not forget to have a plan to back up the NAS itself - RAID has no assurances, and the chance of failure is statistically higher with the number of drives in the arrary (n/1 because disks can and do fail)

A1 - QNAP and Synology are both fine solutions
A2 - For devices currently on the market - check the compatibility lists that the vendor provide, that will give you some idea of what is supported, as that is what the vendor has tested
A3 - Totally possible - it can make the storage pool assignments a bit complicated later on, but there's no restriction
A4 - within a given set, it is always best to pick them together
A5 - JBOD, then RAID0, then RAID1, RAID5, RAID10 and so forth

with 4 drives of 4TB each

JBOD/RAID0 - 16TB - RAID0 will be much more performant than JBOD
RAID1- 8TB, as half the arrary mirrors the other half
RAID5 - 12TB - 3 disks for storage, 1 for parity - slow on writes (speed of one disk), fast on reads
RAID10 - 8TB - RAID10 is usually either 2 RAID1 arrarys, or 2RAID0 arrays - depends on the vendor

I would suggest looking at 3.5 vs. 2.5 for the NAS - better drive choices, and many (Synology for example) can accept either side depending on the model.

 

[coxhaus]

The Synology DS620slim only supports 2.5 disks so only small SSD or laptop hard drives so probably not something you have lying around.

If you are talking striping, then you are talking RAID. RAID5 is the most efficient use of hard disks, but you need at least 3 disks for a RAID5. The more disks you have the faster the RAID is. In a RAID5 all the drives need to be the same size or at least the RAID will be based on the smallest sized disk and any other larger disks can't be used in the RAID. RAID5 will be the fastest in a large drive configuration 8 or more drives.

A mirror wastes the most disk space. It is a 2-disk system and 1 disk is wasted space in terms of a RAID. You do get twice the read speed but a slower write speed.
I would not recommend RAID0 on a NAS as you have twice the failure point with 2 drives. I ran it on a workstation back in the old days when I had a server to back up my data.
RAID10 is a mirror of a mirror and has fast reads in small configurations still slow in writes.

 

[mando2023]

While NAS is a nice place to centralize backups, do not forget to have a plan to back up the NAS itself - RAID has no assurances, and the chance of failure is statistically higher with the number of drives in the arrary (n/1 because disks can and do fail)

A1 - QNAP and Synology are both fine solutions
A2 - For devices currently on the market - check the compatibility lists that the vendor provide, that will give you some idea of what is supported, as that is what the vendor has tested
A3 - Totally possible - it can make the storage pool assignments a bit complicated later on, but there's no restriction
A4 - within a given set, it is always best to pick them together
A5 - JBOD, then RAID0, then RAID1, RAID5, RAID10 and so forth

with 4 drives of 4TB each

JBOD/RAID0 - 16TB - RAID0 will be much more performant than JBOD
RAID1- 8TB, as half the arrary mirrors the other half
RAID5 - 12TB - 3 disks for storage, 1 for parity - slow on writes (speed of one disk), fast on reads
RAID10 - 8TB - RAID10 is usually either 2 RAID1 arrarys, or 2RAID0 arrays - depends on the vendor

I would suggest looking at 3.5 vs. 2.5 for the NAS - better drive choices, and many (Synology for example) can accept either side depending on the model.

Thank you very much for your reply,
mando2023

Following your advice, I am looking now at Synology DS1522+ (around $1200 CAD, tax included) 5Bay

File systems
• Internal: Btrfs, ext4
• External: Btrfs, ext4, ext3, FAT32, NTFS, HFS+, exFAT

Q1: what is the difference between Internal and External?
Q2: what is Btrfs? Is it possible to stream and/or download/upload from other devices in real time?
So, I guess what I am asking is: if I have a media file in mp4 format and I store it on one of the disks of my NAS, will that file be converted to Btrfs? At that point, in order to consume that file, will I have to download it to some device and play it locally, or I can stream it?
I guess, I've seen some NAS labeled as "personal cloud" ... are they all "personal clouds" or is it just some very special ones that are/

Thanks,
mando2023

 

[mando2023]

The Synology DS620slim only supports 2.5 disks so only small SSD or laptop hard drives so probably not something you have lying around.

If you are talking striping, then you are talking RAID. RAID5 is the most efficient use of hard disks, but you need at least 3 disks for a RAID5. The more disks you have the faster the RAID is. In a RAID5 all the drives need to be the same size or at least the RAID will be based on the smallest sized disk and any other larger disks can't be used in the RAID. RAID5 will be the fastest in a large drive configuration 8 or more drives.

A mirror wastes the most disk space. It is a 2-disk system and 1 disk is wasted space in terms of a RAID. You do get twice the read speed but a slower write speed.
I would not recommend RAID0 on a NAS as you have twice the failure point with 2 drives. I ran it on a workstation back in the old days when I had a server to back up my data.
RAID10 is a mirror of a mirror and has fast reads in small configurations still slow in writes.

Thank you very much for your reply!
mando2023

 

[sfx2000]

Q1: what is the difference between Internal and External?

Synology has external chassis one can use to add addtional drives to the system - QNAP has this as well.

Q2: what is Btrfs? Is it possible to stream and/or download/upload from other devices in real time?

Linux, just like Windows, has to have a file system so that files can be stored on them - EXT4 is the most common out there for current Linux - BTRFS (pronounce this better fs) is an alternative, and really is a next generation file system similar to ZFS (Sun/Oracle) and APFS (Apple).

Synology offers this as a choice when setting up the array, along with either doing it old school with LVM, or using their SHR implementation.

SHR, BTRFS is what Synology recommends, and there's a lot to like about it - they have a couple of white papers that discuss in detail, better to get it from them rather than have me try to summarize it on a forum post.

So, I guess what I am asking is: if I have a media file in mp4 format and I store it on one of the disks of my NAS, will that file be converted to Btrfs? At that point, in order to consume that file, will I have to download it to some device and play it locally, or I can stream it?

Files themselves are not changed when you copy them to/from the NAS (at least they are not supposed to) - the file system doesn't convert them in any way/shape/form...

I guess, I've seen some NAS labeled as "personal cloud" ... are they all "personal clouds" or is it just some very special ones that are/

"Personal Cloud" is a marketing term - again, I'll defer to them to describe it in full detail so you can weigh out the pros and cons - I don't use it personally, as I don't have a need for that kind of functionality.

BTW - the SD1522+ is a nice box, but it's likely overkill for most home usage...

the 4bay DS423+ is great choice for a 4 bay NAS for storage, backup, and multimedia playback (let's say via Plex media server) - the 423+ is a 4 core Intel efficiency CPU (aka Atom), but it has a GPU that supports Intel Quick Sync Video which can help with transcoding on the fly to client player software.

I would also look at the DS420+ - it's not the most recent, the 423+ is kind of replacing it in the lineup - so there could be some very good deals to be had if one shops around.

Have you thought about drives yet?

Seagate Ironwolf, WD RedPlus (non-SMR) are good choices... <-- edited for WD Red - go with the plus or pro - regular RED's can and likely are SMR, which isn't good for a RAID

If you're still inclined towards synology - give SpaceRex a view over on the Tube... he's got a whole series of videos on Synology gear...

https://www.youtube.com/channel/UC_n6DdR6FClpCbWnNM7Zp6A

 

[mando2023]

Synology has external chassis one can use to add addtional drives to the system - QNAP has this as well.



Linux, just like Windows, has to have a file system so that files can be stored on them - EXT4 is the most common out there for current Linux - BTRFS (pronounce this better fs) is an alternative, and really is a next generation file system similar to ZFS (Sun/Oracle) and APFS (Apple).

Synology offers this as a choice when setting up the array, along with either doing it old school with LVM, or using their SHR implementation.

SHR, BTRFS is what Synology recommends, and there's a lot to like about it - they have a couple of white papers that discuss in detail, better to get it from them rather than have me try to summarize it on a forum post.



Files themselves are not changed when you copy them to/from the NAS (at least they are not supposed to) - the file system doesn't convert them in any way/shape/form...



"Personal Cloud" is a marketing term - again, I'll defer to them to describe it in full detail so you can weigh out the pros and cons - I don't use it personally, as I don't have a need for that kind of functionality.

BTW - the SD1522+ is a nice box, but it's likely overkill for most home usage...

the 4bay DS423+ is great choice for a 4 bay NAS for storage, backup, and multimedia playback (let's say via Plex media server) - the 423+ is a 4 core Intel efficiency CPU (aka Atom), but it has a GPU that supports Intel Quick Sync Video which can help with transcoding on the fly to client player software.

I would also look at the DS420+ - it's not the most recent, the 423+ is kind of replacing it in the lineup - so there could be some very good deals to be had if one shops around.

Have you thought about drives yet?

Seagate Ironwolf, WD Red (non-SMR) are good choices...

If you're still inclined towards synology - give SpaceRex a view over on the Tube... he's got a whole series of videos on Synology gear...

https://www.youtube.com/channel/UC_n6DdR6FClpCbWnNM7Zp6A

Thank you very much, sir!
I guess I am starting to understand how this NAS works.
Thank you very much for the further info sources recommended, I will do my homework.

IronWolf 16 TB was my first choice.
I will try to do the calculation myself: how much effective space do I have on 4 drives x 16 TB with a RAID5 setup.

Thanks again,
mando2023

 

[sfx2000]

IronWolf 16 TB was my first choice.

Good choice - go for the regular IronWolf, not the Pro variant. They're pretty quiet on idle, but you'll get some pretty affirmative head seeking noise, just as a heads up...

WD Red's are quieter, but after the whole SMR mess, I can't recommend which ones to look at purchasing - the RedPlus line is supposed to be CMR, which is ok, with Red it depends...

Western Digital Announces Red Plus HDDs, Cleans Up Red SMR Mess with Plus Branding

www.anandtech.com

WD's site is down right now (big whohaa on a data breach and that has affected their Web Site as well as their "My Cloud" service)...

 

[coxhaus]

Thank you very much, sir!
I guess I am starting to understand how this NAS works.
Thank you very much for the further info sources recommended, I will do my homework.

IronWolf 16 TB was my first choice.
I will try to do the calculation myself: how much effective space do I have on 4 drives x 16 TB with a RAID5 setup.

Thanks again,
mando2023

RAID5 disk calculation is N-1. Just subtract 1 drive off the number in the RAID5. So 4-1 would be 16 x 3 =48 gig.

A couple of things with RAID5 make sure you don't turn on write cache without a good UPS. The RAID5 will be a lot faster with write cache but it will corrupt the RAID5 if you lose power. I would want a UPS for a RAID NAS anyway. In the server world you run battery back up on the RAID controllers as well. Home systems tend not to have this.

 

[sfx2000]

RAID5 disk calculation is N-1. Just subtract 1 drive off the number in the RAID5. So 4-1 would be 16 x 3 =48 gig.

Yep, and the risk of failure is the inverse

A couple of things with RAID5 make sure you don't turn on write cache without a good UPS. The RAID5 will be a lot faster with write cache but it will corrupt the RAID5 if you lose power. I would want a UPS for a RAID NAS anyway. In the server world you run battery back up on the RAID controllers as well. Home systems tend not to have this.

Absolutely - a UPS is a no-brainer, and the UPS doesn't need to keep the machine up the whole time - both Syno and QNAP have options to do a clean shutdown after a period of time (I have 5 mins) if power is not restored...

APC is good, so is Cyberpower - I have APC, and if I recall, @coxhaus has something similar...

 

[coxhaus]

I only use APC. Probably because I have been using APC for around 30 years with good results.

I used some Triplite power conditioners before there were battery backups but that was with my IBM 286 PC monochrome. I still have a Triplite not being used now. It would still work if I needed it.

The bigger the RAID5 the more you need to be careful when you have a drive fail. You need to let it repair and rebuild. IT can take a long while depending on the CPU. This is where servers shine over a NAS as they have a lot more CPU power. and the controllers are better.

 

[eightiescalling]

I'm a little surprised at the discussion on raid5 given the disk size. For a long time now there's been a school of thought that the stress of a rebuild process has too high a chance of a second disk failure for big disks in a raid5 setup. For example https://superuser.com/questions/912673/are-raid-5-systems-suitable-for-larger-disk-sizes

The cost/benefits between raid5, raid6 and raid10 will depend on your specific needs though.

For disks, while Seagate has had a bad rep for a while I tend to agree with @sfx2000 -i bought a set of ironwolfs when they were relatively new partially as the quoted URE level was better than WD disks and not had any issues (even now the only negative write ups I can find tend to be related to historical opinion). WDs antics quietly swapping between CMR and SMR without fessing up until the PR but them is a reason I'd be loathe to consider the now unless as a straight swap for an existing system. (Appreciate I only count as a survey of 1 though!)

 

[coxhaus]

There are trade offs for all the RAIDs. You have to decide what you want. My last RAID5 in my house was 8 hard disk Segates. It was an Intel RAID controller connected to a SuperMicro hot swap back plane. It had an APC 1500 rack UPS to back it up. I ran it for 4 or 5 years. I installed it on Microsoft Home sever. There are refences here I made to it years ago.

 

[tgl]

Good choice - go for the regular IronWolf, not the Pro variant. They're pretty quiet on idle, but you'll get some pretty affirmative head seeking noise, just as a heads up...

Yeah. I have a DS420+ stuffed with IronWolf Pro drives, and the only thing I don't like about it is the noise level when active. If it's in a server closet, or otherwise well away from your desk, it'll be fine --- but you won't like having it right beside you. Maybe the non-Pro IronWolf is materially quieter, I can't say. Next time I'm buying SSDs.

 

[coxhaus]

My data needs at home are not that great. If I build another RAID at home it will be SSDs. I currently have a single drive NAS that spends most of its life turned off protecting my pictures. I turn it on every couple of months and copy my pictures to it and then turn it off.