geek's intro to NAS NAS are dedicated boxes that presents logical disk volumes on th net built out of local disks inside. They can talk many different protocols (SMB for windows, AFS for macs and NFS for linux.) They are usually configured to allow for disks to fail and be replaced.
The disks in a NAS can be configured in a number of ways, often referred to as RAID (redundant array of inexpensive disks.) The most common ones are RAID 1, RAID 5, RAID 6 and RAID 10. RAID 1 is mirroring. Every write is done to each of a pair of disks. Reads can be done from either disk. If one disk fails, you can always build a new partner from the working disk. Highest reliability but the least efficient storage (2x) RAID 5 is an N+1 parity model. If you have 4 data disks and a parity disk, then you only spend an extra 25% on disk space. RAID 5 requires compute cycles, but with a NAS that's built in. RAID 5 is no longer considered safe in production, as the failure rate and disk size make a double failure risk too high. Generally better to use powers of 2 for the number of data disks. RAID 6 is similar to RAID 5 but with two parity disks. Raid 10 is like RAID 1 except multiple pairs of disks are made into 1 volume. Now come all the things that can bite you: THE NAS is really good at detecting when disks die completely. It may be slow (many hours) but it can rebuild and go on while it is rebuilding. The NAS is useless at catching bit rot on the disks. If the disk is working but you develop an area that has lost its data, you have no idea unless you read those blocks. So if you have rot on disk 1 and disk 2 dies hard, you are SOL. I use a file system called ZFS on a freenas system (easy to roll your own.) It has a function called scrub that walks all the used file storage blocks on a disk and makes sure there is no bit rot. I run this weekly. There are others good file systems like BTRFS, but that always seem to be in the ready for production really soon state. Many NAS systems are pretty aggressive about timing out disks that don't respond and there are many disks that can get into states that a perfectly good drive gets tied out by the NAS. NAS ready drives (like the WD red) are designed to not have this problem. It sucks to have to pay more for a trivial firmware change, but it's probably worth it. Enterprise drives are not worth the money for most users. A NAS does not protect you against file deletes, the most common reason to have to recover files. They also aren't much use for disaster recovery, since they are in the same building as the systems. ZFS and some other file systems also have snapshots, that suck up lots of disk but allow you to go back to the disk at a given time. So backups are still critical. One last bit of sysadmin preaching: You are NOT doing backups unless you regularly test the recovery of files. I can't count the number of time when people have all these tapes, but when something goes wrong they find out that the tapes don't work, the files weren't on it or some other thing. I have done it to myself as well. jerry On Wed, Nov 4, 2015 at 3:29 PM, <richsh...@comcast.net> wrote: > Been using a Zyxel NAS-320 device with two WD Red hard drives, real > hardware RAID, simple to setup, works straight away with Linux, and was > inexpensive. Basic box was about $150.00 / $175.00 not including the > drives. Been running non stop for at least two years. > > ----- Original Message ----- > > From: emc-users-requ...@lists.sourceforge.net > To: emc-users@lists.sourceforge.net > Sent: Wednesday, November 4, 2015 7:09:10 AM > Subject: Emc-users Digest, Vol 115, Issue 15 > > Send Emc-users mailing list submissions to > emc-users@lists.sourceforge.net > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.sourceforge.net/lists/listinfo/emc-users > or, via email, send a message with subject or body 'help' to > emc-users-requ...@lists.sourceforge.net > > You can reach the person managing the list at > emc-users-ow...@lists.sourceforge.net > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Emc-users digest..." > > > Today's Topics: > > 1. Re: Desktops and OS's (Dave Cole) > 2. Re: Desktops and OS's (Gene Heskett) > 3. Re: Desktops and OS's (Gene Heskett) > 4. Re: raid NAS (Jack Coats) > 5. Re: Desktops and OS's (Jim Craig) > 6. Re: Desktops and OS's (Jim Craig) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 4 Nov 2015 09:43:53 -0500 > From: Dave Cole <linuxcncro...@gmail.com> > Subject: Re: [Emc-users] Desktops and OS's > To: emc-users@lists.sourceforge.net > Message-ID: <563a19a9.5080...@gmail.com> > Content-Type: text/plain; charset=windows-1252; format=flowed > > > > --- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus > > > > > ------------------------------ > > Message: 2 > Date: Wed, 4 Nov 2015 09:50:32 -0500 > From: Gene Heskett <ghesk...@wdtv.com> > Subject: Re: [Emc-users] Desktops and OS's > To: emc-users@lists.sourceforge.net > Message-ID: <201511040950.32539.ghesk...@wdtv.com> > Content-Type: Text/Plain; charset="iso-8859-1" > > On Wednesday 04 November 2015 09:10:56 John Thornton wrote: > > > I see that from time to time on my LAN which I have two Windoze and 5 > > or 6 Linux computer on it. Usually only a reboot will fix the Windoze > > computers while the Linux computers IIRC will fix themselves if you > > power cycle the router or switch they are attached to. I think it is > > just a software issue but who knows... > > > > JT > > It is John. Its evidence you are using dhcp as the hook means. > Things may have improved over the years since 10-04, but I've only used > dhcp in the router to get me an ipv4 address for the router, everything > else is host file based. My /etc/hosts file: > ======================================= > 127.0.0.1 localhost > 192.168.xx.1 router.coyote.den router > 192.168.xx.3 coyote.coyote.den coyote > 192.168.xx.4 shop.coyote.den shop > 192.168.xx.5 lathe.coyote.den lathe > 192.168.xx.6 lappy.coyote.den lappy > 192.168.xx.10 GO704.coyote.den GO704 > ======================================== > Identical on all machines > > And my /etc/resolv.conf from any machine > ========================= > search this-machines-name > nameserver 192.168.xx.1 > order host,dns > ========================= > This one made immutable with a sudo chattr +i specifically to keep > network-mangler from mangling it if its still installed. > > Then you can configure /etc/network/interfaces to look something like > this: > ====================== > # list of interfaces to bring up at boot > auto lo eth0 > > # interface lo > iface lo inet loopback > address 127.0.0.1 > netmask 255.0.0.0 > > # interface eth0 > iface eth0 inet static > address 192.168.xx.3 > netmask 255.255.255.0 > gateway 192.168.xx.1 > ======================== > Where the last number of the eth0 address is that machine. > > And if network-mangler is still installed, sudo chattr +i that file too > to keep it from being re-written by mangler. In wheezy, N-M can be > removed. > > On all the linux machines. > > I don't do windows, any flavor, so I can't advise on that. But the last > time I setup a neighbors windows machine, that is exactly what I did as > he had a router that could NAT, so I made it so. > > > > On 11/4/2015 8:01 AM, Rick Lair wrote: > > > Maybe not the right place to ask, but, regarding the networking, why > > > would randomly you not be able to see other network computers? Right > > > now from either my winxp desktop, or my ubuntu 10.04 desktop, I > > > can't see any of the other network computers, or my machines. > > > Connection issues, bad hardware? > Can you ping them by name? > Can you get their address from an ifconfig report on each machine, then > go ping them by address from another machine? > > The latter, as long as they are all in the same class D address space but > you can't ping them by address, I'd say you have hardware problems. > > > > Rick > > > > > > On 11/4/2015 8:27 AM, John Thornton wrote: > > >> If he is doing that from a Windoze computer you can configure the > > >> right click Send To for each machine so it's a one click op to send > > >> the file. > > >> > > >> JT > > >> > > >> On 11/4/2015 7:16 AM, Rick Lair wrote: > > >>> It was an absolute requirement that I got that to work, probably > > >>> like yours, we now have multiple machines in the shop running > > >>> Linuxcnc, and thumb drives are easy to lose, so I have all the > > >>> machines networked together, so the guy in the office that makes > > >>> the programs, can drop the finished g code program right into the > > >>> nc_files folder in the respective machine, right from his desk. > > >>> > > >>> > > >>> Rick > > >>> > > >>> On 11/4/2015 8:09 AM, John Thornton wrote: > > >>>> Sweet, and it works! What a PITA to have to do this just to get > > >>>> an OS to do basic things. I'm still hoping someone will chime in > > >>>> that has built a real time kernel for Linux Mint so I can try > > >>>> that. > > >>>> > > >>>> JT > > >>>> > > >>>> On 11/4/2015 6:55 AM, Rick Lair wrote: > > >>>>> Now you should be able to right click on the the folder icon you > > >>>>> want tot share, see the "Share" tab, and be able to click down > > >>>>> through and setup folder sharing on your network for that > > >>>>> respective folder, > > >>>>> > > >>>>> On 11/4/2015 7:51 AM, John Thornton wrote: > > >>>>>> Hi Rick, > > >>>>>> > > >>>>>> I followed the directions for adding folder sharing to Thunar > > >>>>>> but don't see any difference. What is is supposed to do? > > >>>>>> > > >>>>>> JT > > >>>>>> > > >>>>>> On 11/3/2015 9:59 AM, Rick Lair wrote: > > >>>>>>> John, > > >>>>>>> > > >>>>>>> Attached are some of my notes that I have found to be working > > >>>>>>> in regards to sharing over the network on Debian. > > >>>>>>> > > >>>>>>> You may have already tried these, but this is what I have > > >>>>>>> found. > > >>>>>>> > > >>>>>>> Rick > > >>>>>>> > > >>>>>>> On 11/3/2015 10:44 AM, John Thornton wrote: > > >>>>>>>> Samba is installed... > > >>>>>>>> > > >>>>>>>> On 11/3/2015 9:26 AM, andy pugh wrote: > > >>>>>>>>> On 3 November 2015 at 15:19, John Thornton <j...@gnipsel.com> > wrote: > > >>>>>>>>>> Networking is also hosed up on my Debian computers and try > > >>>>>>>>>> as I might I can't share files as freely around my LAN with > > >>>>>>>>>> the Debian computers. > > >>>>>>>>> > > >>>>>>>>> You nay need to install Samba, it isn't there by default. I > > >>>>>>>>> don't know if Avahi is or not. > > [trimmed 5 list sigs] > > Cheers, Gene Heskett > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author) > Genes Web page <http://geneslinuxbox.net:6309/gene> > > > > ------------------------------ > > Message: 3 > Date: Wed, 4 Nov 2015 09:52:54 -0500 > From: Gene Heskett <ghesk...@wdtv.com> > Subject: Re: [Emc-users] Desktops and OS's > To: emc-users@lists.sourceforge.net > Message-ID: <201511040952.54887.ghesk...@wdtv.com> > Content-Type: Text/Plain; charset="iso-8859-1" > > On Wednesday 04 November 2015 09:43:53 Dave Cole wrote: > (twice) > > --- > > This email has been checked for viruses by Avast antivirus software. > > https://www.avast.com/antivirus > > Are you speechless Dave? :-) > > Cheers, Gene Heskett > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author) > Genes Web page <http://geneslinuxbox.net:6309/gene> > > > > ------------------------------ > > Message: 4 > Date: Wed, 4 Nov 2015 08:54:00 -0600 > From: Jack Coats <j...@coats.org> > Subject: Re: [Emc-users] raid NAS > To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > Message-ID: > <cafq0n1wow9-geq2aur+b6shvslb-tcekppldyfuy1tmpaas...@mail.gmail.com> > Content-Type: text/plain; charset=UTF-8 > > This turned out to be longer than I wanted, but it addresses several > issues. I hope it helps someone: > > > The least expensive version of RAID uses two mirrored drives ( RAID 1 > ). Others get a bit more complicated, but they are worth considering > if you need larger amounts of storage. > > There are home NAS available that don't have RAID or mirroring. I > would stay away from those, they are just a network attached disk > drive. > > Any drive CAN be used as drives for RAID devices. There are ones that > are specially designed for RAID use, like Western Digital RED drives, > and there are others from different manufacturers. > > Backing up using something like CRASHPLAN or better yet, something > that specifically supports your NAS device, is great. You can even > backup a NAS manually to another NAS or even just a USB attached disk > drive. > > On backups, any backup is good for 'awe shucks' problems (accidently > overwrote or deleted a file). But for 'disaster recovery' (your house > took a lightning hit and fried the electronics - it happened to me), > the 3-2-1 backup scheme helps. 3 separate backups, on 2 different > media, and 1 of the off-site. > > Personally, I use CRASHPLAN and backup machines to on-site USB > attached drives and off the the CRASHPLAN data center. -- This is for > me and my family, possibly not for your business. If you use > CRASHPLAN and you have a good internet connection, you can backup to a > computer at another location (like at grandma's house across town, or > at the office, or a friends house). CRASHPLAN is not perfect and I am > just a user and no ties other than that. It is cross platform > compatible from Linux, Windows, and I think Apple (I don't have > those). Pretty easy to set up. > > BTW, there are other great backup programs out there. And 'file > sharing' programs really don't count (think Dropbox ... I use it too, > but it is a different tool for a different need/use). > > On any backup, they must be monitored and tested. At least every few > months restore a few files to make sure it is doing OK. Being a bit > OCD and ADD, daily detail monitoring I knew was best (and fed my OCD), > but it drove my ADD crazy! Don't stress over it, but do it regularly. > Having software email me 'reports' when things are missed for a few > days, it helps me a lot. > > Oh yes, I am cheap. CRASHPLAN has a 'family plan' for up to 10 > machines for unlimited storage to use their central servers for one > price. If you have some friends that use it, you can backup to THEIR > CRASHPLAN machines for free (this is what you would use to backup to > Grandma's or to a work computer. > > CRASHPLAN is NOT open source, but you can install it for free and give > it a try. There are some good open source programs out there, but > they tend to take a bit more effort to get set up. > > I will never claim to be an expert, but I retired from IT after 35 > years, the first 20 as a developer, the last 15 as a sysadmin on > mainframes, UNIX, and windows systems. The last 10 years was doing > backups and disaster recovery principally. > > I hope this helps a little. > > Enjoy. > > On Wed, Nov 4, 2015 at 8:02 AM, John Thornton <j...@gnipsel.com> wrote: > > Just looking up raid NAS and it looks like there are several levels of > > raid and NAS is a Network Attached Storage. Is there something special > > about NAS or can you do that with any hard drive? > > > > JT > > > > On 11/4/2015 7:35 AM, Jim Craig wrote: > >> I have a raid NAS that I send all of my gcode to. Then I open it > >> directly from the NAS into LinuxCNC. Then I don't have to worry about > >> what machine has the latest code etc. The latest is always on the NAS. > >> And it it is backed up. > > > > > > > ------------------------------------------------------------------------------ > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > -- > ><> ... Jack > > The Four Boxes of Liberty - "There are four boxes to be used in the > defense of liberty: soap, ballot, jury and ammo. Please use in that > order." > "Whatever you do, work at it with all your heart"... Colossians 3:23 > "Anyone who has never made a mistake, has never tried anything new." - > Albert Einstein > "You don't manage people; you manage things. You lead people." - > Admiral Grace Hopper, USN > "Tell me and I forget. Teach me and I remember. Involve me and I > learn." - Ben Franklin > > > > ------------------------------ > > Message: 5 > Date: Wed, 4 Nov 2015 08:56:38 -0600 > From: Jim Craig <jimcraig5...@windstream.net> > Subject: Re: [Emc-users] Desktops and OS's > To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > Message-ID: <563a1ca6.2080...@windstream.net> > Content-Type: text/plain; charset=windows-1252; format=flowed > > Yep, That is one example. Usually the NAS box like you have listed below > will have a processor and one or more NAT devices. Then you can add the > hard drives that you like to the box. Some come with drives included. > usually the OS on the box is a custom one that is based on Linux. > Usually you can remote into the box through a web page that is hosted on > the NAS box. > > I am using a WD MyCloudEX2. I don't know if I would recommend it or not. > It needs external cooling as it does not have built in fans so I have it > setting on a laptop cooling fan thingy. > > I also have a better NAS at the farm office but I can't remember what it > is off the top of my head right now. It is currently hosing 2 HDDs but > can be expanded to 4. > > > On 11/4/2015 8:04 AM, John Thornton wrote: > > Something like this? > > > > > http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.2525288 > > > > JT > > > > On 11/4/2015 7:35 AM, Jim Craig wrote: > >> I have a raid NAS that I send all of my gcode to. Then I open it > >> directly from the NAS into LinuxCNC. Then I don't have to worry about > >> what machine has the latest code etc. The latest is always on the NAS. > >> And it it is backed up. > > > > > ------------------------------------------------------------------------------ > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > > ------------------------------ > > Message: 6 > Date: Wed, 4 Nov 2015 09:09:01 -0600 > From: Jim Craig <jimcraig5...@windstream.net> > Subject: Re: [Emc-users] Desktops and OS's > To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > Message-ID: <563a1f8d.9010...@windstream.net> > Content-Type: text/plain; charset=windows-1252; format=flowed > > My question is was it checked to make sure there were viruses there or > that there weren't any? > > On 11/4/2015 8:52 AM, Gene Heskett wrote: > > On Wednesday 04 November 2015 09:43:53 Dave Cole wrote: > > (twice) > >> --- > >> This email has been checked for viruses by Avast antivirus software. > >> https://www.avast.com/antivirus > > Are you speechless Dave? :-) > > > > Cheers, Gene Heskett > > > > > ------------------------------ > > > ------------------------------------------------------------------------------ > > > ------------------------------ > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > > > End of Emc-users Digest, Vol 115, Issue 15 > ****************************************** > > > ------------------------------------------------------------------------------ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Jerry Scharf FINsix IT 650.285.6361 w 650.279.7017 m ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
