Use E-sata to extend RAID?

Questions about SNMP, Power, System, Logs, disk, & RAID.
Post Reply
ejwbegysv
New here
Posts: 9
Joined: Wed Sep 23, 2009 10:40 pm

Use E-sata to extend RAID?

Post by ejwbegysv » Fri Oct 02, 2009 10:29 pm

Hi!


I have a 439 Turbo, and my question is : can i extend my RAID 5 using e-sata disks? Or are they just JBOD?

My idea is to use this cabinet :
http://www.dustin.se/pd_5010329118.aspx

Is there any maximum TB-size resticions for my RAID 5? Im using ext4.

/Jimmy

User avatar
QNAPJason
QNAP Staff
Posts: 5399
Joined: Thu May 21, 2009 2:14 pm
Location: Taipei

Re: Use E-sata to extend RAID?

Post by QNAPJason » Fri Oct 02, 2009 10:37 pm

Hi Jimmy,
We do not support using eSATA HDDs as part of RAID volume because it can easily destroy the RAID system if accidents happen (forget to connect it back when booting, tripped over, accidental removal).

ejwbegysv
New here
Posts: 9
Joined: Wed Sep 23, 2009 10:40 pm

Re: Use E-sata to extend RAID?

Post by ejwbegysv » Fri Oct 02, 2009 10:50 pm

Hi, Im sure no one is tripping over our NAS here but okey... A reason for your byers to get a new bigger QNAP then? :evil:


Is there anyone that know how to alter the qnap "OS" to get this option??

I love the Qnap but I want to have the abillity to expand the storage...

mdovey
Starting out
Posts: 21
Joined: Tue Aug 18, 2009 4:28 pm

Re: Use E-sata to extend RAID?

Post by mdovey » Sat Oct 03, 2009 8:06 pm

I'm not convinced that anyone spending $1000+ on NAS plus disks is going to leave them lying around in places people could trip over them. Moreover, I would hope that if external disks where disconnected the QNAP would be resilient enough to enable you to recover the RAID when the disks were reconnected.

I think that QNAP may be missing a trick here.

I don't know if the QNAP supports eSATA port multipliers. However the SATA controller in at least the 639 is the Marvell 88SX7042, I believe, which is hardware capable of port multiplier support so presumedly support would be at worst just a firmware upgrade away?

If so QNAP could very easily provide a range of storage extenders for the QNAP models which have eSATA - the storage extender being more or less a SATA backplane and PSU in similar boxes to the current QNAP range. If priced correctly I think these would sell quite well.

Matthew

i4icarus
New here
Posts: 4
Joined: Mon Nov 24, 2008 12:55 pm

Re: Use E-sata to extend RAID?

Post by i4icarus » Fri Oct 09, 2009 5:33 pm

This option of volume expansion is now offered by Synology (DX5 that works with DS 509+). The units look great together as they share the same cosmetic. I really hope that Qnap would follow.

Derek

ejwbegysv
New here
Posts: 9
Joined: Wed Sep 23, 2009 10:40 pm

Re: Use E-sata to extend RAID?

Post by ejwbegysv » Fri Oct 09, 2009 7:24 pm

i4icarus wrote:This option of volume expansion is now offered by Synology (DX5 that works with DS 509+). The units look great together as they share the same cosmetic. I really hope that Qnap would follow.

Derek


Hmm.. Ill take a look at Synology, thank you!!

mdovey
Starting out
Posts: 21
Joined: Tue Aug 18, 2009 4:28 pm

Re: Use E-sata to extend RAID?

Post by mdovey » Fri Oct 09, 2009 11:30 pm

i4icarus wrote:This option of volume expansion is now offered by Synology (DX5 that works with DS 509+). The units look great together as they share the same cosmetic. I really hope that Qnap would follow.

Derek


That is precisely what I was talking about. It looks like Synology has got there first (and it seems a little on the expensive side) - but I think some similar devices for extending the 639 etc. they would sell well!

Matthew

User avatar
Don
Guru
Posts: 11986
Joined: Thu Jan 03, 2008 4:56 am
Location: Long Island, New York

Re: Use E-sata to extend RAID?

Post by Don » Sat Oct 10, 2009 12:01 am

Correct me if I am wrong, and I'm sure someone will, but wouldn't using multiple eSata disks via a multiplier in a raid set up cause performance issues? The eSata connector can transfer at 3gb/s so with one drive connected I can (theoretically) achieve 3gb/s to that device. With two drives attached thru the same connector wouldn't I only get 1.5gb/s to each drive when writing to both drives at the same time? With three drives I'd only get 1gb/s and so on. It's one pipe being shared by multiple devices. Am I looking at this wrong?
Read the Online Manuals and use the forum search feature before posting.

It is a recommended to use RAID and have external backups. RAID will protect you from disk failure, keep your system running, and data accessible while the disk is replaced and the RAID rebuilt. Backups will allow you to recover data that is lost or corrupted, or from system failure. One does not replace the other.

Submit bugs and feature requests to QNAP via their Helpdesk app.

NAS: TVS-882BR | F/W: 4.3.6.0895 | 40GB | 2 x M.2 SATA RAID 1 (System/VMs) | 4 x M.2 NMVe QM2-4P-384A RAID 5 (Cache) | 5 x 4TB HDD RAID 6 (Data) | 1 x Blu-ray
NAS: TVS-663 | F/W: 4.4.1.1086 | 16GB | 2 x M.2 NMVe QM2-2P RAID 1 (Cache) | 4 x 4TB RAID 5
Apps: Boinc, Squid, DNSMasq, PLEX, iDrive, QVPN, QLMS, MP3fs, HBS, Entware, DLstation, +others

mdovey
Starting out
Posts: 21
Joined: Tue Aug 18, 2009 4:28 pm

Re: Use E-sata to extend RAID?

Post by mdovey » Sat Oct 10, 2009 3:02 am

You aren't wrong but

a) unless you are using SSDs or velociraptors it is unlikely that the harddisk itself will cope with data transfer anywhere near 3Gbit/s (typically <1Gbit/s - see http://www.seagate.com/docs/pdf/en-GB/d ... a_es_2.pdf for instance)
b) when using RAID the processing power for calculating the parity stripe tends to be the limiting factor rather than disk bandwidth
c) most benchmarking reviews for QNAP put performance for RAID5 at about 80-100Mbyte/s which implies that even the internal SATA bus is not exercised above 1Gbit/s (probably due to parity processing being the bottleneck)
d) if you are using RAID5 you will only be writing at most to 2 disks simultaneously at any one time, if RAID6 at most to 3 disks simultaneously
e) in most circumstances you'll be accessing the NAS via ethernet (so limited to 1Gbit/s or possibly 2Gbit/s if you pair both network interfaces)

So if you are maxing out the transfer speed of your harddisks (at around 1Gbit/s) and maxing out the typically performance seen by the QNAPs (at around 100MBytes/s or 800Mbits/s) you can write to three disks simultaneously without hitting the eSATA 3Gbit/s limit and thats the maximum number of disks a typical RAID5 or RAID6 will be writing to at any one time.

That said you probably would not be interested in such an extension box if performance was your primary concern - if performance were key you'd probably fork out for a complete new second NAS. However, for those for whom space is more important than performance, an extension box like the synology DX5 should be more than adequate.

Matthew

ejwbegysv
New here
Posts: 9
Joined: Wed Sep 23, 2009 10:40 pm

Re: Use E-sata to extend RAID?

Post by ejwbegysv » Sat Oct 10, 2009 3:15 am

Thanks all for all the info/concerns/pros, we are now looking for a self built FreeNAS server now because we want to have the ability to use very large volumes...

:D

A old xeon server and some SATA-raid PCI-e cards with freenas :mrgreen:

The purpose is Backup

Post Reply

Return to “System & Disk Volume Management”