Melhore o desempenho de SSDs RAID (sem TRIM) com desfragmentação periódica de disco? Falta de TRIM mesmo importante?

Question

Não tenho experiência em configurar RAIDs ou usar SSDs, mas estou pensando em comprar uma configuração SSD RAID (potencialmente RAID 10, mas talvez RAID 0) e tenho feito muita pesquisa. Muitas pessoas estão dizendo que a falta de TRIM significa que o desempenho vai se degradar horrivelmente com o tempo, devido a ter que reescrever blocos semi-escritos repetidamente.

Do meu entendimento muito vago do problema, pensei que talvez executar um defrag de disco seria capaz de empurrar todos os dados espalhados de um conjunto de drives envelhecido em blocos concentrados, deixando muitos blocos livres prontos para gravações rápidas, talvez resolvendo toda a questão.

Eu estava apenas imaginando se alguém com uma melhor compreensão do funcionamento de SSDs e configurações de RAID poderia me dizer se uma desfragmentação ocasional poderia resolver o problema "falta de TRIM"?

Além disso, a falta de TRIM é um problema, já que os SSDs modernos fazem parte de sua própria coleta de lixo?

Obrigado antecipadamente

    

Answer 1

Desfragmentar um SSD não melhorará o desempenho, na verdade, poderá diminuir o desempenho devido ao fato de que muitas cópias de arquivos seriam feitas, enchendo o SSD com mais lixo para o coletor de lixo SSD:

Defragmenting an SSD is a terrible idea, for several reasons:

The key benefit to SSDs is that they have virtually no seek time. Reading adjacent blocks of data is no faster than reading blocks that are spread out over the drive. Fragmentation does not affect SSD drive speed.

As I discussed in my SSD Remaining Drive Life article, SSD drives physically wear out as you write to them. Defragmentation software moves around all the files on your drive. Thus, defragmenting an SSD reduces its life span without giving you any benefits.

SSD drives deal with the limited lifespan of their memory cells by using wear-leveling algorithms. These algorithms take advantage of the fact that fragmentation does not affect the drive’s speed. They purposely fragment the drive so that its cells wear out evenly, even if you’re constantly overwriting a small set of files (e.g. database fiels) and never overwriting other files (e.g. operating system files).

Modern SSDs even lie to the operating system. If the operating system tells the drive to save a file in blocks 728, 729, and 730, the drive may decide to write it to blocks 17, 7829, and 78918 instead, if it determines that those blocks haven’t been worn out as much yet. The drive keeps a lookup table of all its blocks, so that when the OS wants to read blocks 728 through 730, the drive reads blocks 17, 7829, and 78918. With such drives, defragmentation software can’t possibly work. The software will think and tell the user that file X was nicely defragmented and stored in blocks 728, 729, and 730, while it actually has no idea where the data is stored physically on the drive.

Conclusion: don’t waste your time and your SSD’s life expectancy by defragmenting it. The automatic defragmentation in Windows 7 skips SSDs automatically. In Vista, you can disable it via the Performance Information and Tools item in the Control Panel. I do strongly recommend you upgrade to Windows 7 if you have an SSD, so you get TRIM support.