[SOLVED] SanDisk Cruzer Force - write/erase cycles

[TheFlash1300]

Hello. Recently, i bought a USB drive, SanDisk Cruzer Force, with a storage amount of 64 gigabytes. Since USB drives don't support S.M.A.R.T, i can't see how many write/erase cycles my USB has.

So, can someone, who is familiar with USBs and the technology SanDisk uses in their USBs, tell me how many write/erase cycles my USB has?

As far as i know, modern USBs have between 10,000 to 1000,000 write cycles. But, i don't know if this is a lot or not. I don't know how much is one cycle. Is one cycle 1GB, meaning that if my USB has 10,000 write/erase cycles, this means that once the total amount of written/deleted data reaches 10,000GB, the USB will enter read-only mode?

I would like to know how many cycles does my USB has, and how much GB is one cycle. I mean, how many gigabytes have to be written in order for the USB to lose one cycle. and become from 10,000 to 9,999?

 

[hotaru.hino]

A write cycle is simply when a flash cell is refreshed for writing. Assuming the USB stick has a basic flash memory controller, it'll likely be doing some rudimentary wear leveling so that it writes to less used cells over used ones. However, refreshes for writing can only happen on pages of storage, and this can vary in size from 4KiB to say 1MB or 2MB.

The worst case scenario with this in mind is if the controller reserves a 2MB page per file regardless of size and assuming perfect wear leveling, you'll run through an entire cycle after about 32,000 files have been written, assuming they're all under 2MB.

Either way, this isn't anything to really worry about as long as this isn't data you can't live without and the only copy is on this USB thumb drive. Thumb drives are cheap, use it however you want and if it croaks, oh well.

 

[Maxxify]

To get a general idea you want to take total NAND writes (not host) divided by the raw capacity of the drive. For example, 100TB of NAND writes on a 1TB drive would be approximately 100 program/erase cycles (PEC). The endurance of the flash is dependent on a variety of factors but primarily the quality - if by "USB" you mean a USB flash drive, this tends to be inferior media-grade. Current media-grade flash tends to be 700 PEC at most.

Older USB drives could come with MLC or SLC, although cheaper drives in your range might have been planar/2D TLC which was pretty awful (you can tell by performance if nothing else). On the other hand, flash usually outlasts its rating. I would expect 700 PEC at most with that drive, though. It's important to realize that other factors can impact this wear, for example temperatures, so it's only a ceiling.

So this would be ~45TB of writes but if you can only check host writes on the drive you should assume a write amplification factor (WAF) between 1.5 and 3.0, which means an effective ceiling around 15TB. Given it's like 2D/planar TLC I'd put the floor around 6.5TB of hosts writes. Check SMART with CrystalDiskInfo (CDI) or similar.

As a side note: modern TLC tends to be rated in the 1500-3000 PEC range although we have 5000-10000 as well (commercial grade, new architectures). Most can survive up to 10000 PEC. These will be rated for 30000-40000 PEC in SLC mode but in a typical drive, dynamic SLC can even reduce endurance with additive writes. You don't see 100000 PEC except for native SLC which is prohibitively expensive and is not really used even on insane USB drives (there are some exceptions here and native SLC can be higher, but I'm talking consumer-available).