bigslash
Enthusiast
Enthusiast

2 node vsan on a community sd-card

Hi to all,

one of our customer is angry about the prices of the sd-cards on their servers.The price is about 200$ for 1 sd-card .

So the customer asked me that ,instead of buying these cards, lets buy 2 cheap cards,and install esxi on them ,and also but another 2 sdcard for offline.

we will install esxi to all sd-cards and keep 2 of them offline , whenever its needed ,he will replace the broken one with the new.

This sounds good in an normal esxi environment, since if we dont have any backups,and the vms are on the shared storage ,it doesnt create a big problem.

But in 2 node Vsan environment, we couldnt make the desicion ,any ideas ?

Regards

10 Replies
daphnissov
Immortal
Immortal

The price is about 200$ for 1 sd-card

On what planet does an SD card cost $200??!! And for what size? All you need is a 16 or 32 GB card. They're less than ten bucks on Amazon for a good one.

0 Kudos
a_p_
Leadership
Leadership

Well, may be not the answer that you'd probably get from official support (VMware, or HW-vendor).

Some of my customers do the same thing. They are using consumer SD-Cards, and over the years I can't remember that one of them broke. Please note that the SD-Cards used are not the cheapest ones you can find, but ones that are usually used with good cameras.

André

0 Kudos
sjesse
Leadership
Leadership

https://www.amazon.com/Genuine-Cisco-UCS-SD-64G-S-Gigabit-Digital/dp/B077SSPGWN They are out there, I just would like to see the write endurance on this compared to consumer one.

0 Kudos
a_p_
Leadership
Leadership

On what planet does an SD card cost $200??!!

That looks like the list price for a 32/64GB SD-Card from some major server vendors. Even though nobody would ever pay the list price, even the reduced price is usually beyond good and evil.


André

0 Kudos
daphnissov
Immortal
Immortal

Server vendors just OEM the cards from manufacturers like Kingston and SanDisk. There's absolutely no sane reason to pay that amount for an SD card for ESXi, because for a similar amount you could just buy a SATADOM drive.

0 Kudos
nachogonzalez
Expert
Expert

Hey, hope you are doing fine.
Using SD cards should be fine.
I've seen environments with cheap SD's and no issues, nevertheless if you want extra "security" I'd recommend you lexar SD's https://www.amazon.com/-/es/Lexar-Professional-633x-64GB-UHS-I/dp/B012PL6K8M/ref=sr_1_1?__mk_es_US=%...

https://www.amazon.com/-/es/Lexar-Professional-2000x-UHS-II-Reader/dp/B00OD71AYQ/ref=sr_1_2?__mk_es_...

They are a little bit more expensive than OEM SD's nevertheless those are the ones used for video and photography.
I've been using the same 2SD cards for photo and video with no issues for the last 3 years.

Hope that works

0 Kudos
bigslash
Enthusiast
Enthusiast

Thanks for all of your answers,

The price is really very high (it is still a list price ,but they wont make a big reduction in the list price ).

It seems quite ok to buy the cheap ones, but still i have a doubt about the worst scenario.What will happen if one of them fails ,

Will the vsan environment will broke down (it mustnot be ) ,since its 2 node vsan ,we are still not very sure of the consequences ??

thanks for your time and answers

0 Kudos
depping
Leadership
Leadership

I would personally be more worried about 'end-to-end' support for the solution to be honest. If something breaks, who says the OEM will support you when you use uncertified USB/SD devices? That is typically the challenge.

We have a document explaining our requirements: ESXi Hardware Requirements

Personally, i'd prefer satadom or decent m.2 devices these days, as it allows you to store logs etc locally without being afraid that the devices fails every other week. Just makes things easier, and less dependent on external locations.

TheBobkin
VMware Employee
VMware Employee

Hello bigslash​,

"Will the vsan environment will broke down (it must not be ) ,since its 2 node vsan ,we are still not very sure of the consequences ??"

No. Should the boot device fail in one node, provided you are applying the default FTM=RAID1,FTT=1 Storage Policy to all data, the VMs data should remain accessible and be able to run on the remaining node - do bear in mind that adequate compute resources will be required to run all the VMs on the remaining node (or at least know which non-critical VMs will need to remain powered off until the issue is resolved).

Speaking from a VMware GSS perspective: SD-card failures are commonly not binary events (e.g. where they are either functioning or they are not, though this can of course occur), a lot of the times when we see issue with devices that are clearly on the way out, things can get fairly unstable but not instantly nor predictably, so if you are planning on going with the cheap unsupported option then do at least consider having a reasonable replacement interval (e.g. at least every year) and/or some means or process of monitoring or periodically checking vmkernel.log for the signs of these devices degrading.

That being said, I 100% agree with what depping said above in that you are taking this in your own hands with these choices and that options such as M.2 are preferable (especially as this is a remote deployment from what you have said and thus where are you planning to store persistent logs etc. if there is no other storage?).

Also, don't forget that if you are buying devices from a vendor then these *generally* come with good replacement warranties should they fail prematurely and potentially on-site service/replacement in a short timeframe (I say potentially as unsure with SDs but this is the case with other disk devices with sufficient levels of vendor support) - in the long-term this may be more cost-effective and less hassle than someone having to drive to this site at 4AM to replace yet another melted SD-card.

Buy cheap, buy twice (well hopefully it is only twice :smileygrin: )

Bob

0 Kudos
IRIX201110141
Virtuoso
Virtuoso

Some notes:

  • >100 of Hosts with Dual SD card setup here the failure ratio it not higher as HDD in our setups (we have tons of "diskless" servers without RAID HBA, Backplane, Slots to save money). This is valid when speaking of 1-5 years life time
  • New cards from Dell costs around 60,- ( we ordered a few last year)
  • As all flash like media it will wear out. I dont expect that the SD will work after 7 years or so... but we have HDDs which are >14 years old
  • As long as the Host HW is under warranty the SD card will be replaced. Do you run production workload on HW without warranty?
  • vSphere ESXi as an OS will require today more space as 10 years ago. The first SD cards where rather small like 1-2GB or so. So this boot media cant use for ever because it can be to small some day
  • Replacing a SD in  a ROBO is P.I.A because the Hosts needs to be opened

ESXi 7.0 have changed the partition layout (OS_DATA... yes i'm aware that its possible to decrease the size if you want) and it looks that VMware would like to see a larger boot device today and i cant think that it will decrease in the future. Right now Dell dont offer pre installed ESXi 7.0 on SD cards.

Now about vSAN related things

  • Scratch partitions can only be specify on VMFS/NFS? and not vSAN. The SD dont offer a VMFS datastore
  • Hosts with large memory needs some space if you need to save memory dumps
  • For me these 2x M.2 SSD boot devices  (Dell BOSS) are the future when it comes to vSAN setups

Regards,
Joerg