Examining Solid State Drives as Part of Modern Storage Stacks and Large-Scale Enterprise Storage Systems
Notice bibliographique
Résumé
System reliability is arguably one of the most important aspects of a storage system and as such, a large body of work exists on the topic of storage device reliability. Considering that more data is being stored on solid state drives (SSDs), we study the reliability characteristics of NAND-based SSDs deployed in enterprise storage systems, including several factors that were not studied before. The findings of our study contradict common expectations, highlighting the importance of constantly evaluating the reliability of storage systems as new technologies and devices emerge. Furthermore, as we increasingly rely on SSDs for data storage, it is also important to understand what their operational characteristics look like in the field. Compared to HDDs, the performance and expected lifespan of an SSD are affected by operational characteristics in fundamentally different ways. For instance, SSDs require background work, such as garbage collection, which generates write amplification, thereby affecting both a drive's performance and lifespan. We present the first large-scale field study of key operational characteristics of SSDs in enterprise storage systems, while focusing on the drives' write rates, level of write amplification and how it is affected by various factors, along with the effectiveness of wear leveling. Next, we study the reliability characteristics of modern file systems, running on top of flash-based SSDs. Given the growing adoption of SSDs as a form of secondary storage medium, storage reliability also depends on the ability of higher levels within the storage stack to handle any errors these devices might generate. The results of our analysis indicate that file systems frequently cannot be mounted or even repaired. Based on our findings, we file several bug reports and also recommend several design guidelines tailored for file systems running on top of SSDs. In the last part of this thesis, we focus on system configuration, as the overall performance and reliability of a storage system are both affected by its underlying configuration. We present a detailed study on system configurations in production environments, while focusing on the characteristics of RAID groups, along with the number of total spare SSDs available. Finally, considering that systems need to adapt to increasing capacity needs during their lifetime, we additionally present the frequency and characteristics of system expansions and reconfigurations, as observed for real-world production systems.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,001 |
| Méta-épidémiologie (sens large) | 0,002 | 0,000 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 0,002 |
| Science ouverte | 0,002 | 0,002 |
| Intégrité de la recherche | 0,001 | 0,002 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; les deux têtes enseignantes s’accordent sur ce qui est montré ici.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».