hw writes:
On Thu, 2022-11-10 at 23:05 -0500, Michael Stone wrote: > On Thu, Nov 10, 2022 at 06:55:27PM +0100, hw wrote: > > On Thu, 2022-11-10 at 11:57 -0500, Michael Stone wrote: > > > On Thu, Nov 10, 2022 at 05:34:32PM +0100, hw wrote:> > > > And mind you, SSDs are *designed to fail* the sooner the more data you> > > > write > > > > to > > > > them. They have their uses, maybe even for storage if you're so > > > > desperate, > > > > but > > > > not for backup storage.
[...]
Why would anyone use SSDs for backups? They're way too expensive for that.
I actually do this for offsite/portable backups because SSDs are shock resistant (dont lose data when being dropped etc.).
The most critical thing to acknowledge about using SSDs for backups is that the data retention time of SSDs (when not powered) is decreasing with each generation.
Write endurance has not become critical in any of my SSD uses so far. Increasing workloads have also resulted in me upgrading the SSDs. So far I always upgraded faster than running into the write endurance limits. I do not use the SSDs as caches but as full-blown file system drives, though.
On the current system, the SSDs report having written about 14 TB and are specified by the manufacturer for an endurance of 6300 TBW (drive size is 4 TB). The small (drive size about 240GB) ones I use for backup are much less durable. For one of them, the manufacturer claims 306TBW, the other has 360 TBW specified. I do not currently know how much data I have written to them already. As you can see from the sizes, I backup only a tiny subset of the data to SSDs i.e. the parts of my data that I consider most critical (VM images not being among them...).
[...]
There was no misdiagnosis. Have you ever had a failed SSD? They usually justdisappear. I've had one exception in which the SDD at first only sometimes disappeared and came back, until it disappeared and didn't come back.
[...]Just for the record I recall having observed this once in a very similar fashion. It was back when a typical SSD size was 60 GiB. By now we should mostly be past this “SSD fails early with controller fault” issues. It can still happen and I still expect SSDs to fail with less notice compared to HDDs.
When I had my first (and so far only) disk failure (on said 60G SSD) I decided to:
* Retain important data on HDDs (spinning rust) for the time being * and also implement RAID1 for all important drivesAlthough in theory running two disks instead of one should increase the overall chance of having one fail, no disks failed after this change so far.
YMMV Linux-Fanöö
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