Cache Disk Problems - need to remove it

[SliMat]

Hi All

 

I added a cache disk (120Gb SSD) a little while ago and immeditaley realised it wouldnt do what I wanted... so decided to remove it - but as per an earlier post I reaslied that there is so much data on it I dont want to just remove it and lose any data. So I am after advice on how to do this.

 

My thoughts are to stop all my dockers and VMs and then invoke mover to ensure all data is returned from the cache disk to the array disks. Then change global share settings to "use cache disk - No", then just remove the SSD and start again.

 

My concern is that there are a number of shares which are flagged as "SOME OR ALL FILES ARE UNPROTECTED" as you can see in this screenshot there are a number of shares which are using the cache disk and are flagged as unprotected - I guess because it thinks some current data is on the cache drive;

 

However these shares are all set to "Use cache disk - No" under the share settings, so I have no idea why there is data from these shares on the cache disk...

 

Can anyone help?

 

In short what I was trying to do was to add a cache disk to be used for a VM image as the image is hammering my array disks.. so I wanted to confine it to the cache disk which can be replaced if it fails rather than risking having disks fail in the main array. So, I need to remove the current cache disk (As I am going to use an enterprise class 2.5" disk instead) then to install this new disk and copy my VM image on to it.

 

Any pointers will be appreciated... oh, you will see that it is in the middle of a parity check so I know I cant start this for a few hours

 

Thanks

 

 

[JorgeB]

Change all those shares to use cache = "yes" and run the mover, files can't be in use so before doing it you need to stop the docker and VM services, etc.

[SliMat]

26 minutes ago, johnnie.black said:

Change all those shares to use cache = "yes" and run the mover, files can't be in use so before doing it you need to stop the docker and VM services, etc.

 

Thanks Johnnie - I'll try that once the parity check is complete.

[pwm]

2 hours ago, SliMat said:

so I wanted to confine it to the cache disk which can be replaced if it fails rather than risking having disks fail in the main array.

 

There is a quite low probability that running dockers on an array HDD will result in a disk breaking. They can handle quite a lot of head seeks during a lifetime.

 

The main advantage of using a SSD cache for docker and VM is that:

- the main array can stop all disks and so reduce noise and heat

- the SSD gives many times faster reads/writes since it doesn't have head seek times

 

The obvious disadvantage is that unless you have a redundant cache pool, you need a method to regularly (much more often, since you should never be without backup)  make a backup of your docker storage locations and VM

[SliMat]

Thanks pwm - I only have a couple of dockers - mariadb-nextcloud and nextcloud and a few VMs (1 x Ubuntu Server - 80Gb, 1 x Windows 7 PC - 30Gb, 1 x Windows SBS 2011 server - 200Gb, 1 x Debian Server - 20Gb)... but what you are saying makes a lot of sense as I have noticed that the array disks never spin down now since I installed the dockers and VMs.

 

As the machine is in my living room I do want to keep noise to a minimum, so... If I replace the existing 120Gb SSD with a 1Tb Enterprise SATA disk (non SSD)... is it easy to move the dockers and VMs to run on this only? Then when I can afford a 500Gb SSD drive to replace the 1Tb one, can I just clone the disk using something like Acronis TrueImage - or is there a way to install the new SSD and copy the original cache drive data over? To complicate things I am using an HP MIcroserver... so, without lots of messing about, I can only connect 5 disks at a time... (3 x array disks, 1 x parity disk + 1 cache disk) so if you suggest adding the new SSD cache disk as a sixth drive to copy the data over I would have to use the slot for the parity (or one of the array) disks to allow this.

 

If the space allows I might be able to use the 500Gb SSD cache disk as a store for my dockers/vms and as a cache disk too?!?!

 

Many thanks to all for the ongoing lesson

[pwm]

The N54L microservers I have can handle 4 disks in the RAID and have a fifth internal SATA for a CD and an ESATA connector. So I can fit 5 HDD and then draw a cable from ESATA to an internal cache or use with an external enclosure. The newer microservers removed the physical space for the CD

[SliMat]

I'll check mine... its the newer G8 version, so not the N54L which I had before this one. Mine shipped with the G2020 CPU, but I have upgraded it to a Xeon E3-1220v2 CPU. It has 4 x 3.5" caddies and then space for the laptop style DVD - I have converted the power feed for this so I have my 2.5" SSD SATA cache disk sitting here - so as you can see I am really limited on how many disks I can fit without doing some radical chopping around. Haven't noticed if there is an ESATA connector on the back - so will have a look tonight!

[SliMat]

43 minutes ago, pwm said:

The N54L microservers I have can handle 4 disks in the RAID and have a fifth internal SATA for a CD and an ESATA connector. So I can fit 5 HDD and then draw a cable from ESATA to an internal cache or use with an external enclosure. The newer microservers removed the physical space for the CD

 

Just checked - as I thought the G8 doesnt have an eSATA port - but I have a spare PCIe slot and a spare 4-port Adaptec SATA RAID card which will fit... so I can fit this and twin the power feed to my existing cache disk to allow a sixth disk to be fitted in order to migrate stuff from the existing 120Gb cache disk to a temporary 1Tb disk and then back to a new larger SSD cache disk when I get it Once this is all resolved and the 500Gb SSD cache disk is fitted I should have room to fit a sixth disk to use as a second cache disk... if theres a benefit to doing this?

 

Thanks

[SliMat]

8 hours ago, johnnie.black said:

Change all those shares to use cache = "yes" and run the mover, files can't be in use so before doing it you need to stop the docker and VM services, etc.

 

Thanks Johnnie... did exactly that and invoked mover and now the cache disk is clear... so will set shares to no and remove the small SSD disk and replace it with the 1Tb disk and try to work out how to move the dockers and VMs on to it until I get a larger SSD to host them.